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Monitoring the Future (MTF) is a long-term study of American adolescents, college students, and adults through age 55. It has been conducted annually by the University of Michigan's Institute for Social Research since its inception in 1975 and is supported under a series of investigator-initiated, competing research grants from the National Institute on Drug Abuse. The 2013 MTF survey encompassed about 41,700 8th-, 10th-, and 12th-grade students in 389 secondary schools nationwide. The first published results are presented in this report. Recent trends in the use of licit and illicit drugs are emphasized, as well as trends in the levels of perceived risk and personal disapproval associated with each drug. This project has shown these beliefs and attitudes to be particularly important in explaining trends in use. In addition, trends in the perceived availability of each drug are presented. The report begins with a synopsis of the design and methods used in the study and an overview of the key results from the 2013 survey. This is followed by a separate section for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (1) using the drug; (2) seeing a "great risk" associated with its use (perceived risk); (3) disapproving of its use (disapproval); and (4) saying that it would be fairly or very easy to get if they wanted to (perceived availability). For 12th graders, annual data are available since 1975 and for 8th and 10th graders since 1991, the first year they were included in the study. [For "Monitoring the Future National Survey Results on Drug Use, 1975-2013. Volume 1, Secondary School Students," see ED578546.]

This occasional paper presents national demographic subgroup trends for U.S. secondary school students in a series of figures and tables. It supplements two of four annual monographs from the Monitoring the Future (MTF) study, namely the "Overview of Key Findings" and "Volume I: Secondary School Students." MTF is funded by the National Institute on Drug Abuse under a series of investigator-initiated, competitive research grants. The full 2013 survey results are reported in "Monitoring the Future National Survey Results on Drug Use, 1975-2013: Volume I, Secondary School Students." That monograph contains a description of MTF's design and purposes, as well as extended reporting on substance use of all kinds, licit and illicit, and a number of related factors such as attitudes and beliefs about drugs, age of initiation, non-continuation of drug use, perceived availability, relevant conditions in the social environment, history of daily marijuana use, use of drugs for the treatment of ADHD, and sources of prescription drugs used outside of medical supervision. Until 2012, "Volume I" contained the tabular data on trends in drug use for various demographic subgroups that are now presented in the present occasional paper. The trends offered here in tabular form and graphic form--the latter for ease of comprehension--cover demographic subgroups based on: (1) gender; (2) college plans; (3) region of the country; (4) population density; (5) education level of the parents (a proxy for socioeconomic level); and (6) racial/ethnic identification. Detailed descriptions of the demographic categories are provided in a separate chapter. The graphs and tables in this occasional paper present trend data for 8th-, 10th-, and 12th-grade respondents. Data for 12th grade begins with 1975, the first year in which a nationally representative sample of high school seniors was surveyed. Data for 8th and 10th grades begin with 1991, when the study's annual surveys were expanded to include those grade levels. [For "Monitoring the Future National Survey Results on Drug Use, 1975-2013. Volume 1, Secondary School Students," see ED578546. For "Monitoring the Future National Survey Results on Drug Use, 1975-2013: Overview, Key Findings on Adolescent Drug Use," see ED578545.]

This occasional paper presents subgroup findings from the Monitoring the Future (MTF) study on levels of and trends in the use of a number of substances for nationally representative samples of high school graduates ages 19-30. The data have been gathered in a series of follow-up surveys of representative subsamples of high school seniors who were first surveyed in 12th grade as part of the MTF study. Therefore, the universe being described omits people who did not complete high school--between 9-15% of each age group, with the most recent class cohorts closer to the bottom of that range. Surveys of the graduating cohorts of high school seniors started in 1976 and have continued with each graduating class since. Data were first available for the 19-22 age group in 1980 and for the older age groups in subsequent years, as the tables and figures in this occasional paper indicate. The general epidemiological findings from these samples are contained in "Volume II" of the annual monograph series. The subgroup trends shown in the current occasional paper complement the last section of Chapter 5 (Trends in Drug Use in Early and Middle Adulthood) of that monograph by presenting the trend data for young adult subgroups in both graphic and tabular form. The results are described and discussed in Chapter 5, but the extensive set of tables and figures is provided here for the reader who wishes to view the figures and the underlying numerical values. Three demographic dimensions are differentiated: gender, region of the country, and population density. Gender includes trends for males and females, region describes trends for each of the four major regions defined by the U.S. Census, and population density differentiates trends for five levels of urbanicity. The Table of Contents and List of Figures are actively linked to the content and figures in this occasional paper. Following each figure is a table giving the numerical values associated with each trend line in that figure. [For "Monitoring the Future National Survey Results on Drug Use, 1975-2013. Volume 2, College Students & Adults Ages 19-55," see ED578547.]

Monitoring the Future (MTF) is a long-term study of American adolescents, college students, and adults through age 50. It has been conducted annually by the University of Michigan's Institute for Social Research since its inception in 1975 and is supported under a series of investigator-initiated, competing research grants from the National Institute on Drug Abuse. The 2011 the MTF survey encompassed about 46,700 8th-, 10th-, and 12th-grade students in 400 secondary schools nationwide. The first published results are presented in this report. Recent trends in the use of licit and illicit drugs are emphasized, as well as trends in the levels of perceived risk and personal disapproval associated with each drug. This study has shown these beliefs and attitudes to be particularly important in explaining trends in use. In addition, trends in the perceived availability of each drug are presented. A synopsis of the design and methods used in the study and an overview of the key results from the 2011 survey is presented in the introductory section. These are followed by a separate section for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (a) using the drug, (b) seeing a "great risk" associated with its use (perceived risk), (c) disapproving of its use (disapproval), and (d) saying they could get it "fairly easily" or "very easily" if they wanted to (perceived availability). For 12th graders, annual data are available since 1975, and for 8th and 10th graders, since 1991, the first year they were included in the study. The tables at the end of this report provide the statistics underlying the figures; in addition, they present data on lifetime, annual, 30-day, and (for selected drugs) daily prevalence. (Contains 17 tables and 9 footnotes.) [For "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2010," see ED528077.]

Monitoring the Future (MTF), which is now in its 36th year, is a research program conducted at the University of Michigan's Institute for Social Research under a series of investigator-initiated research grants from the National Institute on Drug Abuse. The study is comprised of several ongoing series of annual surveys of nationally representative samples of 8th- and 10th-grade students (begun in 1991), 12th-grade students (begun in 1975), and high school graduates into adulthood (begun in 1976). The current monograph reports the results of the repeated cross-sectional surveys of high school graduates since 1976 as the authors follow them into their adult years. Several segments of the general adult population are covered in these follow-up surveys: (1) American college students; (2) Their age peers who are not attending college, sometimes called the "forgotten half"; (3) All young adult high school graduates of modal ages 19 to 30, which the authors refer to as the "young adult" sample; and (4) High school graduates at the specific later modal ages of 35, 40, 45, and 50. Changes in substance abuse and related attitudes and beliefs occurring at each of these age strata receive particular emphasis. The authors can summarize the findings on trends as follows: For more than a decade--from the late 1970s to the early 1990s--the use of a number of illicit drugs declined appreciably among 12th-grade students, and declined even more among American college students and young adults. These substantial improvements--which seem largely explainable in terms of changes in attitudes about drug use, beliefs about the risks of drug use, and peer norms against drug use--have some extremely important policy implications. One clear implication is that these various substance-using behaviors among American young people are malleable--they can be changed. It has been done before. The second is that demand-side (rather than supply-side) factors appear to have been pivotal in bringing about most of those changes. The levels of marijuana availability, as reported by 12th graders, have held fairly steady throughout the life of the study. (Moreover, among students who abstained from marijuana use, as well as among those who quit, availability and price rank very low on their lists of reasons for not using.) And, in fact, the perceived availability of cocaine was actually rising during the beginning of the sharp decline in cocaine and crack use in the mid- to late- 1980s, which occurred when the perceived risk associated with that drug rose sharply. However, improvements are surely not inevitable; and when they occur, they should not be taken for granted. Relapse is always possible and, indeed, just such a relapse in the longer term epidemic occurred during the early to mid-1990s, as the country let down its guard on many fronts. The drug problem is not an enemy that can be vanquished. It is more a recurring and relapsing problem that must be contained to the extent possible on an ongoing basis. Therefore, it is a problem that requires an ongoing, dynamic response--one that takes into account the continuing generational replacement of children, the generational forgetting of the dangers of drugs that can occur with that replacement, and the perpetual stream of new abusable substances that will threaten to lure young people into involvement with drugs. (Contains 30 tables, 49 figures and 68 footnotes.) [For related reports, see "Monitoring the Future National Survey Results on Drug Use, 1975-2010. Volume I, Secondary School Students" (ED528081); and "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2010" (ED528077).]

The Monitoring the Future (MTF) study involves an ongoing series of national surveys of American adolescents and adults that has provided the nation with a vital window into the important, but largely hidden, problem behaviors of illegal drug use, alcohol use, tobacco use, anabolic steroid use, and psychotherapeutic drug use. For more than a third of a century, MTF has provided a clearer view of the changing topography of these problems among adolescents and adults, a better understanding of the dynamics of factors that drive some of these problems, and a better understanding of some of their consequences. It has also given policymakers and nongovernmental organizations in the field some practical approaches for intervening. This annual monograph series has been the primary vehicle for disseminating MTF's epidemiological findings. This latest two-volume monograph presents the results of the 36th survey of drug use and related attitudes and beliefs among American high school seniors, the 31st such survey of American college students, and the 20th such survey of 8th- and 10th-grade students. Importantly, results are also reported for high school graduates followed in a series of panel studies through age 50. Results from the samples of 8th, 10th, and 12th graders are contained in "Volume I", which is preceded by two national press releases and an advance summary report. Results on college students and other adults are reported each year in "Volume II", which is published a few months after "Volume I". A new monograph was added in 2009 on risk and protective behaviors for the spread of HIV/AIDS among young adults. The authors can summarize the findings on trends as follows: For more than a decade--from the late 1970s to the early 1990s--the use of a number of illicit drugs declined appreciably among 12th-grade students, and declined even more among American college students and young adults. These substantial improvements--which seem largely explainable in terms of changes in attitudes about drug use, beliefs about the risks of drug use, and peer norms against drug use--have some extremely important policy implications. One clear implication is that these various substance-using behaviors among American young people are malleable--they can be changed. It has been done before. The second is that demand-side (rather than supply-side) factors appear to have been pivotal in bringing about most of those changes. The levels of marijuana availability, as reported by 12th graders, have held fairly steady throughout the life of the study. Moreover, among students who abstained from marijuana use, as well as among those who quit, availability and price rank very low on their lists of reasons for not using.) And, in fact, the perceived availability of cocaine was actually rising during the beginning of the sharp decline in cocaine and crack use in the mid- to late- 1980s, which occurred when the perceived risk associated with that drug rose sharply. However, improvements are surely not inevitable; and when they occur, they should not be taken for granted. Relapse is always possible and, indeed, just such a relapse in the longer term epidemic occurred during the early to mid-1990s, as the country let down its guard on many fronts. The drug problem is not an enemy that can be vanquished. It is more a recurring and relapsing problem that must be contained to the extent possible on an ongoing basis. Therefore, it is a problem that requires an ongoing, dynamic response--one that takes into account the continuing generational replacement of children, the generational forgetting of the dangers of drugs that can occur with that replacement, and the perpetual stream of new abusable substances that will threaten to lure young people into involvement with drugs. Appended are: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Subgroups; (3) Estimation of Sampling Errors; (4) Trends by Subgroup: Supplemental Tables for Secondary School Students; (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, Sedatives, and Narcotic Drugs Other than Heroin; and (6) Trends in Drug Use for Three Grades Combined. An index is included. (Contains 242 tables, 123 figures and 131 footnotes.) [For related reports, see "Monitoring the Future National Survey Results on Drug Use, 1975-2010. Volume II, College Students & Adults Ages 19-50" (ED528082); and "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2010" (ED528077).]

Monitoring the Future (MTF) is a long-term study of American adolescents, college students, and adults through age 50. It has been conducted annually by the University of Michigan's Institute for Social Research since its inception in 1975 and is supported under a series of investigator-initiated, competing research grants from the National Institute on Drug Abuse. The 2010 MTF survey encompassed about 46,500 eighth-, 10th-, and 12th-grade students in almost 400 secondary schools nationwide. The first published results are presented in this report. Recent trends in the use of licit and illicit drugs are emphasized, as well as trends in the levels of perceived risk and personal disapproval associated with each drug. This study has shown these beliefs and attitudes to be particularly important in explaining trends in use. In addition, trends in the perceived availability of each drug are presented. A synopsis of the design and methods used in the study and an overview of the key results from the 2010 survey follow this report's introductory section. These are followed by a separate section for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (a) using the drug, (b) seeing a "great risk" associated with its use (perceived risk), (c) disapproving of its use (disapproval), and (d) saying they could get it "fairly easily" or "very easily" if they wanted to (perceived availability). For 12th graders, annual data are available since 1975, and for 8th and 10th graders, since 1991, the first year they were included in the study. The tables at the end of this report provide the statistics underlying the figures; in addition, they present data on lifetime, annual, 30-day, and (for selected drugs) daily prevalence. (Contains 17 tables and 9 footnotes.) [For related reports, see "Monitoring the Future National Survey Results on Drug Use, 1975-2010. Volume I, Secondary School Students" (ED528081); and "Monitoring the Future National Survey Results on Drug Use, 1975-2010. Volume II, College Students & Adults Ages 19-50" (ED528082).]

The full 2010 survey results are reported in "Monitoring the Future National Survey Results on Drug Use, 1975;2010: Volume I, Secondary School Students". That monograph contains a description of MTF's design and purposes, as well as extended reporting on substance use of all kinds, licit and illicit, and a number of related factors such as attitudes and beliefs about drugs, age of initiation, non-continuation of drug use, relevant conditions in the social environment, history of daily marijuana use, use of drugs for the treatment of ADHD, and sources of prescription drugs used outside of medical supervision. Appendix D of "Volume I" contains tabular data on trends in drug use for various demographic subgroups for each of the many drugs under study. The present occasional paper presents those same subgroup trends in "graphic form", because graphic presentations are much easier to comprehend. (Showing the trends in color greatly facilitates the differentiation of the various trend lines in each graph.) Historically, the graphic presentations have not been included in "Volume I" due both to their length and the cost of printing them in color. Even though the annual monographs from the study now are published electronically on the study's Website, rather than in paper form, the authors continue to make the graphic presentation of the subgroup trends available in this separate document in the MTF Occasional Paper series. Trend data are presented for 12th-grade respondents beginning with 1975, the first year in which a nationally representative sample of high school seniors was surveyed. Trend data for 8th and 10th grades are presented beginning with 1991, when the study's annual surveys were expanded to include those grade levels. The numerical information upon which these graphics are based is contained in the relevant appendix D tables of "Volume I". Detailed definitions of the demographic categories are given in appendix B of that volume. (Contains 258 figures.)

Now in its 35th year, Monitoring the Future (MTF) is a long-term program of research conducted at the University of Michigan's Institute for Social Research under a series of investigator-initiated research grants from the National Institute on Drug Abuse. The study is comprised of several ongoing series of annual surveys of nationally representative samples of 8th- and 10th-grade students (begun in 1991), 12th-grade students (begun in 1975), and high school graduates into adulthood (begun in 1976). The current monograph reports the results of the repeated cross-sectional surveys since 1976 following graduating high school seniors into their adult years. Several segments of the general adult population are covered in these follow-up surveys: (1) American college students; (2) Their age peers who are not attending college, sometimes called the "forgotten half"; (3) All young adult high school graduates of modal ages 19 to 30, which the authors refer to as the "young adult" sample; and (4) High school graduates at the specific modal ages of 35, 40, 45, and 50. Changes in substance abuse and related attitudes and beliefs within each of these various age strata receive particular emphasis. The authors can summarize the findings on trends as follows: For more than a decade--from the late 1970s to the early 1990s--the use of a number of "illicit" drugs declined appreciably among 12th-grade students, and declined even more among American college students and young adults. In 1992, eighth graders exhibited a significant increase in annual use of "marijuana," "cocaine," "LSD," and "hallucinogens other than LSD," as well as an increase in "inhalant" use. Over the years, MTF has demonstrated that changes in perceived risk and disapproval have been important causes of change in the use of a number of drugs. These beliefs and attitudes are almost certainly influenced by the amount and nature of public attention paid to the drug issue in the historical period during which young people are growing up. Another lesson that derives from the MTF epidemiological data is that social influences that tend to reduce the "initiation" of substance use also have the potential to deter "continuation" by those who have already begun to use, particularly if they are not yet habitual users. The drug problem is not an enemy that can be vanquished. It is more a recurring and relapsing problem that must be contained to the greatest extent possible on an ongoing basis. Therefore, it is a problem that requires an ongoing, dynamic response--one that takes into account the continuing generational replacement of children, the generational forgetting of the dangers of drugs that can occur with that replacement, and the perpetual stream of new abusable substances that will threaten to lure young people into involvement with drugs. An index is included. (Contains 30 tables, 74 figures and 64 footnotes.) [For related reports, see "Monitoring the Future National Survey Results on Drug Use, 1975-2009. Volume I, Secondary School Students. NIH Publication Number 10-7584" (ED529150) and "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2009. NIH Publication Number 10-7583" (ED529149).]

Monitoring the Future (MTF), now in its 35th year, has become one of the nation's most relied-upon sources of information on changes taking place in licit and illicit psychoactive drug use among American adolescents, college students, young adults, and more recently, middle-aged adults. During the last three and a half decades, the study has tracked and reported on the use of an ever-growing array of such substances in these populations. This annual series of monographs is one of the major vehicles by which the epidemiological findings from MTF are reported. Findings from the inception of the study in 1975 through 2009 are included--the results of 35 national in-school surveys and 33 national follow-up surveys. MTF has conducted in-school surveys of nationally representative samples of (a) 12th-grade students each year since 1975 and (b) 8th- and 10th-grade students each year since 1991. In addition, beginning with the class of 1976, the project has conducted follow-up mail surveys on representative subsamples of the respondents from each previously participating 12th-grade class. These follow-up surveys now continue well into adulthood. A number of important findings have been summarized in this report to provide the reader with an overview of the key results. Because so many populations, drugs, and prevalence intervals are discussed here, a single integrative set of tables (Tables 2-1 through 2-4) show the 1991-2009 trends for all drugs on five populations: 8th-grade students, 10th-grade students, 12th-grade students, full-time college students modal ages 19-22, and all young adults modal ages 19-28 who are high school graduates. (Note that the young adult group includes the college student population.) "Volume II" also contains data on older age bands based on the longer term follow-up surveys: specifically, ages 35, 40, 45, and 50. An index is included. (Contains 30 tables, 74 figures, and 64 footnotes.) [For Volume I, see ED514370.]

The Monitoring the Future (MTF) study is an ongoing series of national surveys of American adolescents and adults that has provided the nation with a vital window into the important, but largely hidden, problem behaviors of illegal drug use, alcohol use, tobacco use, anabolic steroid use, and psychotherapeutic drug use. For more than a third of a century, MTF has provided a clearer view of the changing topography of these problems among adolescents and adults, a better understanding of the dynamics of factors that drive some of these problems, and a better understanding of some of their consequences. It has also given policymakers and nongovernmental organizations in the field some practical approaches for intervening. This annual monograph series has been the primary vehicle for disseminating MTF's epidemiological findings. This latest two-volume monograph presents the results of the 35th survey of drug use and related attitudes and beliefs among American high school seniors, the 30th such survey of American college students, and the 19th such survey of 8th- and 10th-grade students. Results are also reported for high school graduates followed in a series of panel studies through age 50. Two of the major topics included in this report are (a) the "prevalence and frequency" of drug use among American secondary school students in 8th, 10th, and 12th grades and (b) "historical trends" in use by students in those grades. Distinctions are made among important demographic subgroups in these populations based on gender, college plans, region of the country, population density, parents' education, and race/ethnicity. The authors can summarize the findings on trends as follows: For more than a decade--from the late 1970s to the early 1990s--the use of a number of "illicit" drugs declined appreciably among 12th-grade students, and declined even more among American college students and young adults. These substantial improvements--which seem largely explainable in terms of changes in attitudes about drug use, beliefs about the risks of drug use, and peer norms against drug use--have some extremely important policy implications. One clear implication is that these various substance-using behaviors among American young people are malleable--they can be changed. Over the years, MTF has demonstrated that changes in perceived risk and disapproval have been important causes of change in the use of a number of drugs. These beliefs and attitudes are almost certainly influenced by the amount and nature of public attention paid to the drug issue in the historical period during which young people are growing up. A substantial decline in attention to this issue in the early 1990s very likely explains why the increases in perceived risk and disapproval among students ceased and began to backslide. Another lesson that derives from the MTF epidemiological data is that social influences that tend to reduce the "initiation" of substance use also have the potential to deter "continuation" by those who have already begun to use, particularly if they are not yet habitual users. The drug problem is not an enemy that can be vanquished. It is more a recurring and relapsing problem that must be contained to the greatest extent possible on an ongoing basis. Therefore, it is a problem that requires an ongoing, dynamic response--one that takes into account the continuing generational replacement of children, the generational forgetting of the dangers of drugs that can occur with that replacement, and the perpetual stream of new abusable substances that will threaten to lure young people into involvement with drugs. Appended are: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Subgroups; (3) Estimation of Sampling Errors; (4) Trends by Subgroup: Supplemental Tables for Secondary School Students; (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, Sedatives, and Narcotic Drugs other than Heroin; and (6) Trends in Drug Use for Three Grades Combined. An index is included. (Contains 242 tables, 123 figures and 129 footnotes.) [For related reports, see "Monitoring the Future National Survey Results on Drug Use, 1975-2009. Volume II, College Students & Adults Ages 19-50. NIH Publication Number 10-7585" (ED529151) and "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2009. NIH Publication Number 10-7583" (ED529149).]

Monitoring the Future (MTF) is a long-term study of American adolescents, college students, and adults through age 50. The study is supported under a series of investigator-initiated, competing research grants from the National Institute on Drug Abuse, and has been conducted annually by the University of Michigan's Institute for Social Research since 1975. The present volume is being published separately for the first time this year. Whereas the other three MTF monographs address the topic of substance use, the present volume focuses on a range of behaviors related to the spread of the human immunodeficiency virus (HIV) responsible for the acquired immunodeficiency syndrome (AIDS). The population under study is young adult high school graduates ages 21-30 in the general population. Previously, findings on this subject were presented as a final chapter in "Volume II" based on measures of HIV/AIDS risk and protective behaviors that were introduced into the MTF follow-up studies in 2004. However, as the content expanded considerably and the historical period lengthened, a separate volume on this important topic seemed warranted. (Contains 18 tables and 3 figures.) [For the related reports, see "Overview of Key Findings" (ED514371), 'Volume I" (ED514370), and "Volume II" (ED514367).]

Monitoring the Future (MTF) is a long-term study of American adolescents, college students, and adults through age 50. It has been conducted annually by the University of Michigan's Institute for Social Research since its inception in 1975. It is supported under a series of investigator-initiated, competing research grants from the National Institute on Drug Abuse. The 2009 MTF survey encompassed over 46,000 eighth-, 10th-, and 12th-grade students in almost 400 secondary schools nationwide. The first published results are presented in this report. Recent trends in the use of licit and illicit drugs are emphasized, as well as trends in the levels of perceived risk and personal disapproval associated with each drug. This study has shown these beliefs and attitudes to be particularly important in explaining trends in use. In addition, trends in the perceived availability of each drug are presented. A synopsis of the design and methods used in the study and an overview of the key results from the 2009 survey follow the introductory section. This is followed by a separate section for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (a) using the drug, (b) seeing a "great risk" associated with its use (perceived risk), (c) disapproving of its use (disapproval), and (d) saying that they think they could get it "fairly easily" or "very easily" if they wanted to (perceived availability). For 12th graders, annual data are available since 1975, and for 8th and 10th graders, since 1991, the first year they were included in the study. The tables at the end of this report provide the statistics underlying the figures; in addition, they present data on lifetime, annual, 30-day, and (for selected drugs) daily prevalence. For the sake of brevity, the authors present these prevalence statistics here only for the 1991-2009 interval, but statistics on 12th graders are available for earlier years in other MTF publications. For each prevalence period, the tables indicate which of the most recent one-year changes (between 2008 and 2009) are statistically significant. The graphic depictions of multiyear trends often indicate gradual, continuing change that may not reach significance in a given one-year interval. (Contains 17 tables and 7 footnotes.) [For related reports, see "Monitoring the Future National Survey Results on Drug Use, 1975-2009. Volume I, Secondary School Students. NIH Publication Number 10-7584" (ED529150) and "Monitoring the Future National Survey Results on Drug Use, 1975-2009. Volume II, College Students & Adults Ages 19-50. NIH Publication Number 10-7585" (ED529151).]

This occasional paper serves as a supplement to one of four annual monographs from the Monitoring the Future (MTF) study, written by the study's investigators and published by the study's sponsor, the National Institute on Drug Abuse. The full 2009 survey results are reported in "Monitoring the Future National Survey Results on Drug Use, 1975-2009: Volume I, Secondary School Students". That monograph contains a description of MTF's design and purposes, as well as extended reporting on substance use of all kinds and a number of related factors such as attitudes and beliefs about drugs, age of initiation, non-continuation of drug use, relevant conditions in the social environment, history of daily marijuana use, and use of drugs for the treatment of ADHD. Appendix D of Volume I contains tabular data on trends in drug use for various demographic subgroups for each of the many drugs under study. The present occasional paper presents those subgroup trends in "graphic" form, because graphic presentations are much easier to comprehend. The graphic presentations have not been included in "Volume I" due both to their length and the cost of printing them in color. Trend data are presented for 12th-grade respondents beginning with 1975, the first year in which a nationally representative sample of high school seniors was surveyed. Trend data for 8th and 10th grades are presented beginning with 1991, when those grade levels were added to the study design. The numerical information upon which these graphics are based is contained in the relevant appendix D tables of Volume I. Detailed definitions of the demographic categories are given in appendix B of that volume. For the reader's convenience, both appendix B and appendix D have also been included in this occasional paper. (Contains 258 figures and 1 footnote.)

Monitoring the Future is a long-term program of research being conducted at the University of Michigan's Institute for Social Research under a series of investigator-initiated research grants from the National Institute on Drug Abuse. Now in its 34th year, the study is comprised of several ongoing series of annual surveys of nationally representative samples of 8th- and 10th-grade students (begun in 1991), 12th-grade students (begun in 1975), and adults (begun in 1976). As the authors report in this volume, several segments of the adult population are covered in the follow-up surveys of high school graduates. One important segment is American college students; a second is their age peers who are not attending college, sometimes called the "forgotten half"; and a third is all young adult high school graduates of modal ages 19 to 30, which are referred to as the "young adult" sample. Finally, high school graduates at the specific modal ages of 35, 40, 45, and 50 are included each year in longer term follow-ups. The follow-up surveys have been conducted by mail on representative subsamples of the previous participants from each high school senior class. The present volume presents data from the 1977 through 2008 follow-up surveys of the graduating high school classes of 1976 through 2007 as these respondents have progressed into adulthood--now through age 50 for the oldest respondents. (Contains 30 tables, 74 figures, and 61 footnotes.) [This content was produced by the Monitoring the Future project at the Institute for Social Research, University of Michigan. For Volume I, see ED508295.]

The Monitoring the Future study has provided the nation with a window into the important, but largely hidden, problem behaviors of illicit drug use, alcohol use, and tobacco use. It has provided a clearer view of the changing topography of these problems among adolescents and adults, a better understanding of the dynamics of factors that drive some of these problems, and a better understanding of some of their consequences. It has also given policy makers and nongovernmental organizations in the field some approaches for reducing these problems. The 2008 survey, reported here, is the 34th in this series of national surveys of substance use among America's young people. Results from the secondary school samples of 8th, 10th, and 12th graders are contained in Volume I, which is preceded by an advance summary of its key findings in "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2008." Two of the major topics included in this series of annual reports are: (1) the prevalence and frequency of drug use among American secondary school students (specifically, in 8th, 10th, and 12th grades); and (2) historical trends in use by students in those grades. Distinctions are made among important demographic subgroups in these populations based on gender, college plans, region of the country, population density, parents' education, and race/ethnicity. Data on grade of first use, trends in use at lower grade levels, as well as intensity of drug use are also reported in separate chapters. This study has demonstrated that key attitudes and beliefs about use of the various drugs are important determinants of trends in use over time. Therefore, they are also tracked over time, as are students' perceptions of certain relevant aspects of the social environment--in particular, perceived availability, peer norms, use by friends, and exposure to use of the various drugs. The following are appended: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Subgroups; (3) Estimation of Sampling Errors; (4) Trends by Subgroup: Supplemental Tables for Secondary School Students; and (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, and Narcotic Drugs Other Than Heroin. (Contains 223 tables, 123 figures, and 125 footnotes.) [This document was produced by the Monitoring the Future project at the Institute for Social Research, the University of Michigan. For Volume II, see ED508297.]

Since the mid-1960s, when illicit drug use burgeoned in the normal youth population, substance use by American young people has proven to be a rapidly changing phenomenon. Smoking, drinking, and illicit drug use are leading causes of morbidity and mortality, both during adolescence as well as later in life. How vigorously the nation responds to teenage substance use, how accurately it identifies the substance abuse problems that are emerging, and how well it comes to understand the effectiveness of policy and intervention efforts depend on the ongoing collection of valid and reliable data. Monitoring the Future (MTF), a long-term study of American adolescents, college students, and adults through age 50, is designed to generate such data in order to provide an accurate picture of what is happening in this domain and why, has been ongoing on an annual basis since its inception in 1975. In recent years, the trends in drug use have become more complex, as cohort effects, lasting differences between class cohorts that stay with them as they advance through school and beyond, have emerged. These effects result in the various grades reaching peaks or valleys in different years; thus, various age groups are sometimes moving in different directions at a given point in history. A synopsis of the design and methods used in the study and an overview of the key results from the 2008 survey are included, followed by sections for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (1) using the drug; (2) seeing a "great risk" associated with its use; (3) disapproving of its use; and (4) saying that they think they could get it "fairly easily" or "very easily" if they wanted to. The years for which data on each grade are available are 1975-2008 for 12th graders and 1991-2008 for 8th and 10th graders. Tables at the end of the report provide the statistics underlying the figures, and present data on lifetime, annual, 30-day, and (for selected drugs) daily prevalence. (Contains 6 footnotes and 17 tables.) [For 2007 overview, see ED502205.]

Monitoring the Future is a long-term program of research being conducted at the University of Michigan's Institute for Social Research under a series of investigator-initiated research grants from the National Institute on Drug Abuse. Now in its 33rd year, the study is comprised of several ongoing series of annual surveys of nationally representative samples of 8th- and 10th-grade students (begun in 1991), 12th-grade students (begun in 1975), and adults (begun in 1976). As the authors report in this volume, several segments of the adult population are covered in the follow-up surveys of high school graduates. One important segment is American college students; a second is their age peers who are not attending college, sometimes called the "forgotten half"; and a third is all young adult high school graduates of modal ages 19 to 30, which are referred to as the "young adult" sample. Finally, high school graduates at the specific modal ages of 35, 40, and 45 are included each year in longer term follow-ups. The follow-up surveys have been conducted by mail on representative subsamples of the previous participants from each high school senior class. The present volume presents data from the 1977 through 2007 follow-up surveys of the graduating high school classes of 1976 through 2006 as these respondents have progressed into adulthood--now through age 45 for the oldest respondents, and soon to be through age 50. (Contains 42 tables, 74 figures, and 59 footnotes.) [This content was produced by the Monitoring the Future project at the Institute for Social Research, University of Michigan. For Volume I, see ED508294.]

The Monitoring the Future study has provided the nation with a window into the important, but largely hidden, problem behaviors of illicit drug use, alcohol use, and tobacco use. It has provided a clearer view of the changing topography of these problems among adolescents and adults, a better understanding of the dynamics of factors that drive some of these problems, and a better understanding of some of their consequences. It has also given policy makers and nongovernmental organizations in the field some approaches for reducing these problems. The 2007 survey, reported here, is the 33rd in this series of national surveys of substance use among America's young people. Results from the secondary school samples of 8th, 10th, and 12th graders are contained in Volume I, which is preceded by an advance summary of its key findings in "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2007." Two of the major topics included in this series of annual reports are: (1) the prevalence and frequency of drug use among American secondary school students (specifically, in 8th, 10th, and 12th grades); and (2) historical trends in use by students in those grades. Distinctions are made among important demographic subgroups in these populations based on gender, college plans, region of the country, population density, parents' education, and race/ethnicity. Data on grade of first use, trends in use at lower grade levels, as well as intensity of drug use are also reported in separate chapters. This study has demonstrated that key attitudes and beliefs about use of the various drugs are important determinants of trends in use over time. Therefore, they are also tracked over time, as are students' perceptions of certain relevant aspects of the social environment--in particular, perceived availability, peer norms, use by friends, and exposure to use of the various drugs. The following are appended: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Subgroups; (3) Estimation of Sampling Errors; (4) Trends by Subgroup: Supplemental Tables for Secondary School Students; and (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, and Narcotic Drugs Other Than Heroin. (Contains 215 tables, 105 figures, and 127 footnotes.) [This document was produced by the Monitoring the Future project at the Institute for Social Research, the University of Michigan. For Volume II, see ED508296.]

Since the mid-1960s, when illicit drug use burgeoned in the normal youth population, substance use by American young people has proven to be a rapidly changing phenomenon. Smoking, drinking, and illicit drug use are leading causes of morbidity and mortality, both during adolescence as well as later in life. How vigorously the nation responds to teenage substance use, how accurately it identifies the substance abuse problems that are emerging, and how well it comes to understand the effectiveness of policy and intervention efforts depend on the ongoing collection of valid and reliable data. Monitoring the Future (MTF), a long-term study of American adolescents, college students, and adults through age 45, is designed to generate such data in order to provide an accurate picture of what is happening in this domain and why, has been ongoing on an annual basis since its inception in 1975. In recent years, the trends in drug use have become more complex, as cohort effects, lasting differences between class cohorts that stay with them as they advance through school and beyond, have emerged. These effects result in the various grades reaching peaks or valleys in different years; thus, various age groups are sometimes moving in different directions at a given point in history. Cohort effects for cigarette smoking were observed throughout most of the life of the study, but such effects were much less apparent for illicit drugs until the past decade and a half. Eighth graders have been the first to show turnarounds in illicit drug use: they were the first to show an upturn in use in the early 1990s and the first to show a decline in use after 1996. They have generally shown the greatest proportional declines from recent peak levels of use, attained for the most part during the 1990s, while the proportional declines have generally been the least at 12th grade. A number of drugs showed modest continuing declines in use in 2007, although few of the one-year changes reached statistical significance. These included marijuana, and all of the stimulant drugs other than cocaine. Most of the other drugs held steady in their use in 2007, generally following decreases in their use in prior years. Only the ecstasy (MDMA) class of drugs under study showed any sign of increase in use in 2007. A synopsis of the design and methods used in the study and an overview of the key results from the 2007 survey are included, followed by sections for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (1) using the drug; (2) seeing a "great risk" associated with its use; (3) disapproving of its use; and (4) saying that they think they could get it "fairly easily" or "very easily" if they wanted to. The years for which data on each grade are available are 1975-2007 for 12th graders and 1991-2007 for 8th and 10th graders. Tables at the end of the report provide the statistics underlying the figures, and present data on lifetime, annual, 30-day, and (for selected drugs) daily prevalence. (Contains 6 footnotes, 17 figures, and 13 tables.) [For 2006 overview, see ED497304.]

This occasional paper is intended to serve as a supplement to the larger annual volume, "Monitoring the Future National Survey Results on Drug Use, 1975-2007: Volume I: Secondary School Students." This supplement contains the graphic presentation of the trends in drug use for various demographic subgroups, namely those defined by gender, college plans, region of the country, population density, education level of the parents, and racial and ethnic identification. It presents trend data for 12th-grade respondents from 1975, the first year nationally representative samples of high school seniors were obtained. Data are also presented on 8th- and 10th-grade students from 1991, the first year they were added. Two appendixes from the larger volume are included for the convenience of the reader. Appendix D contains the numerical information upon which these graphs are based. Appendix B contains detailed information of the demographic categories being used. (Contains 252 figures and 109 tables.) [For "Monitoring the Future Occasional Paper Paper 68," see ED508291. For "Monitoring the Future: National Survey Results on Drug Use, 1975-2007. Volume I: Secondary School Students," see ED508294.]

Monitoring the Future is a long-term program of research being conducted at the University of Michigan's Institute for Social Research under a series of investigator-initiated research grants from the National Institute on Drug Abuse. Now in its 32nd year, the study is comprised of several ongoing series of annual surveys of nationally representative samples of 8th- and 10th-grade students (begun in 1991), 12th-grade students (begun in 1975), and adults (begun in 1976). As the authors report in this volume, several segments of the adult population are covered in the follow-up surveys of high school graduates. One important segment is American college students; a second is their age peers who are not attending college, sometimes called the "forgotten half"; and a third is all young adult high school graduates of modal ages 19 to 30, which are referred to as the "young adult" sample. Finally, high school graduates at the specific modal ages of 35, 40, and 45 are included each year in longer term follow-ups. The follow-up surveys have been conducted by mail on representative subsamples of the previous participants from each high school senior class. The present volume presents data from the 1977 through 2006 follow-up surveys of the graduating high school classes of 1976 through 2005 as these respondents have progressed into adulthood--now through age 45 for the oldest respondents, and soon to be through age 50. An index is also included. (Contains 39 tables, 75 figures, and 58 footnotes.) [This content was produced by the Monitoring the Future project at the Institute for Social Research, University of Michigan. For Volume I, see ED498428.]

The Monitoring the Future study has provided the nation with a window into the important, but largely hidden, problem behaviors of illicit drug use, alcohol use, and tobacco use. It has provided a clearer view of the changing topography of these problems among adolescents and adults, a better understanding of the dynamics of factors that drive some of these problems, and a better understanding of some of their consequences. It has also given policy makers and nongovernmental organizations in the field some approaches for reducing these problems. The 2006 survey, reported here, is the 32nd in this series of national surveys of substance use among America's young people. Results from the secondary school samples of 8th, 10th, and 12th graders are contained in Volume I, which is preceded by an advance summary of its key findings in "Monitoring the Future National Results on Adolescent Drug Use: Overview of Key Findings, 2006." Two of the major topics included in this series of annual reports are: (1) the prevalence and frequency of drug use among American secondary school students (specifically, in 8th, 10th, and 12th grades); and (2) historical trends in use by students in those grades. Distinctions are made among important demographic subgroups in these populations based on gender, college plans, region of the country, population density, parents' education, and race/ethnicity. Data on grade of first use, trends in use at lower grade levels, as well as intensity of drug use are also reported in separate chapters. This study has demonstrated that key attitudes and beliefs about use of the various drugs are important determinants of trends in use over time. Therefore, they are also tracked over time, as are students' perceptions of certain relevant aspects of the social environment--in particular, perceived availability, peer norms, use by friends, and exposure to use of the various drugs. The following are appended: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Subgroups; (3) Estimation of Sampling Errors; (4) Trends by Subgroup: Supplemental Tables for Secondary School Students; and (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, and Narcotic Drugs Other Than Heroin. An Index is also included. (Contains 210 tables, 103 figures, and 122 footnotes.) [This document was produced by the Monitoring the Future project at the Institute for Social Research, the University of Michigan. For Volume II, see ED498426.]

This report provides a summary of drug use trends from a survey of nearly 50,000 eighth-, tenth-, and twelfth- grade students nationwide. It also includes perceived risk, personal disapproval, and perceived availability of each drug by this group. A synopsis of the methods used in the study and an overview of the key results from the 2006 survey follows an introductory section. Next is a section for each individual drug class, providing figures that show trends in the overall proportions of students at each grade level (a) using the drug, (b) seeing a "great risk" associated with its use, (c) disapproving of its use, and (d) saying that they could get it "fairly easily" or "very easily." Drugs covered include: any illicit drug use, marijuana, inhalants, LSD, crack cocaine, amphetamines, methamphetamines and ice, heroin, other narcotics, tranquilizers, sedatives (barbituates), ecstasy and other club drugs, alcohol, cigarettes, smokeless tobacco, and steroids. Annual trends are provided for 8th and 10th graders from 1991-2006, and for 12th graders from 1975-2006. These represent the years for which data on each grade are available. The tables at the end of this report provide the statistics underlying the figures; they also present data on lifetime, annual, 30-day, and (for selected drugs) daily prevalence. Among the findings are that 8th graders have been the first to show turnarounds in illicit drug use: they were the first to show the upturn in use in the early 1990s and the first to show the decline in use after 1996. They now appear to be the first showing an end to many of the declines observed in recent years, leaving the 12th graders as showing further declines for the most part. The report also addresses the "cohort effects" phenomena; "cohort effects" refers to lasting differences between class cohorts that stay with them as they advance through school and beyond. (Contains 13 tables.)

This occasional paper is intended to serve as a supplement to the larger annual volume, "Monitoring the Future National Survey Results on Drug Use, 1975-2006: Volume I: Secondary School Students." This supplement contains the graphic presentation of the trends in drug use for various demographic subgroups, namely those defined by gender, college plans, region of the country, population density, education level of the parents, and racial and ethnic identification. It presents trend data for 12th-grade respondents from 1975, the first year nationally representative samples of high school seniors were obtained. Data are also presented on 8th- and 10th-grade students from 1991, the first year they were added. Two appendixes from the larger volume are included for the convenience of the reader. Appendix D contains the numerical information upon which these graphs are based. Appendix B contains detailed information of the demographic categories being used. (Contains 108 tables and 252 figures.) [For "Monitoring the Future Occasional Paper Paper 66," see ED508289. For "Monitoring the Future: National Survey Results on Drug Use, 1975-2006: Volume I: Secondary School Students," see ED498428.]

In 2005, the Monitoring the Future study marked its 31st year of conducting national surveys of substance use among American young people. Beginning with the first survey of high school seniors in 1975, the study has provided the nation with a window through which to view the important, but largely hidden, problem behaviors of illicit drug use, alcohol use, and cigarette smoking. It has thus enabled the nation to gain a better understanding of the changing nature of these problems, as well as some of their causes and consequences. This annual monograph series has been the primary vehicle for disseminating the epidemiological findings from the study. It has grown substantially over the years in both coverage and size, in part because of the proliferation of substances being used. This latest two-volume monograph presents the results of the 31st (2005) national survey of drug use and related attitudes and beliefs among American high school seniors, the 26th such survey of American college students, and the 15th such survey of 8th- and 10th-grade students. Results have also been reported for varying intervals on young adult high school graduates, as well as adult high school graduates into middle age (currently through age 45) who have been followed from high school graduation through a series of panel studies. Appended are: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Subgroups; (3) Estimation of Sampling Errors; (4) Trends by Subgroup: Supplemental Tables for Secondary School Students; and (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, and Narcotic Drugs Other Than Heroin. (Contains 173 tables and 68 figures.)

This monograph provides the 1975-2005 national trends in smoking, drinking, and illicit drug use among American secondary school students. It covers subgroup differences, attitudes and beliefs about use, social milieu, degree and duration of drug highs, initiation rates, prevalence and frequency, and trends in illicit drug and alcohol use. Drug use by age 45 is also covered. Most of the information reported deals with illicit use of controlled substances. The major exceptions are alcohol, cigarettes, smokeless tobacco, inhalants, nonprescription stimulants, creatine, and androstenedione. This report focuses attention on drug use at the higher frequency levels rather than simply to report proportions that have ever used various drugs. This is done to help differentiate levels of seriousness, or extent, of drug involvement. Over more than a decade--from the late 1970s to the early 1990s--the use of a number of illicit drugs declined appreciably among 12th-grade students, and declined even more among American college students and young adults. These substantial improvements--which seem largely explainable in terms of changes in attitudes about drug use, beliefs about the risks of drug use, and peer norms against drug use--have some extremely important policy implications. Another lesson that derives from the epidemiological data in this study is that social influences that tend to reduce the initiation of substance use also have the potential to deter the continuation of use by those who have already begun to use, particularly if they are not yet deeply involved in use. The following are appended: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Subgroups; (3) Estimation of Sampling Errors; (4) Trends by Subgroup: Supplemental Tables for Secondary School Students; and (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, and Narcotic Drugs Other Than Heroin. (Contains 187 tables and 96 figures.)

This volume--the second in a two-volume set from the Monitoring the Future study--provides findings on the substance use and related behaviors of several segments of the adult population. It also contains findings on attitudes and beliefs about drugs, as well as on several particularly salient dimensions of their social environments. Volume I presents similar findings for American secondary students in grades 8, 10, and 12. One important segment covered here is the population of American college students; a second is their age peers who are not attending college. Also covered in this volume are young adult high school graduates ages 19 to 30 (including the college students), as well as high school graduates at ages 35, 40, and 45. Monitoring the Future is a long-term research program conducted at the University of Michigan's Institute for Social Research under a series of investigator-initiated research grants from the National Institute on Drug Abuse. Now in its 30th year, it comprises, in part, ongoing series of annual nationally representative surveys of 12th- (begun in 1975) and of 8th- and 10th-grade students (begun in 1991). (Contains 31 tables and 79 figures.) [For Volume I, see ED489468. For 2003 edition of Volume II, see ED483832.]

The use of licit and illicit drugs by American young people has been a source of major policy and public health concerns for the United States since the mid-1960s. The use of these substances is a leading cause of eventual disease and death in the population, but it also contributes in important ways to mortality and morbidity during adolescence. Monitoring the Future, which is now in its 29th year, has become one of the nation's most relied-upon sources of information on changes taking place in licit and illicit psychoactive drug use among American adolescents, college students, and young adults. The study has tracked and reported the use of an ever-growing array of such substances in these populations. This annual series of monographs, written by the study's investigators and published by the National Institute on Drug Abuse is one of the major vehicles by which the epidemiological findings from the study are reported. The present two-volume monograph reports findings through 2003. (A companion series of annual reports provides a much briefer, advanced synopsis of the key findings from the latest surveys of secondary school students.) Appended are: (1) Prevalence and Trend Estimates Adjusted for Absentees and Dropouts; (2) Definition of Background and Demographic Sub Groups; (3) Estimation of Sampling Errors; (4) Supplemental Tables for Secondary School Students: Trends by Subgroup; and (5) Trends in Specific Subclasses of Hallucinogens, Amphetamines, Tranquilizers, and Narcotics Other Than Heroin. An index of drugs is also included. (Contains 146 tables and 95 figures.)

This report provides information about drug testing by American secondary schools, based on results from national surveys. The purposes of this study are (1) to provide descriptive information on drug testing practices by schools from 1998 to 2001, and (2) to examine the association between drug testing by schools and reported drug use by students. School-level data on drug testing were obtained through the Youth, Education, and Society study, and student-level survey data were obtained from the same schools participating in the Monitoring the Future study. A relatively small percentage of schools (about 18%) reported testing for drug use, with more high schools than middle schools reporting the use of drug testing. Drug testing was not associated with students' reported illicit drug use, nor with the rate of use among experienced marijuana users. Drug testing athletes was not associated with illicit drug use among male high school athletes. Policy implications are discussed. (Contains 25 references and 5 tables.) (Author)