Demographic Subgroup Trends Among Adolescents in the Use of Various Licit and Illicit Drugs 1975-2013 provides an analysis of drug use among the Monitoring the Future Study (MTF) 1775-2013 survey participants. The MTF study is a nationally representative survey that has been conducted annually among students enrolled in public and private high schools in the United States. Begun in 1975 as a survey of 12th grade students, 8th and 10th grade surveys were added to the series in 1991. Monitoring the Future (MTF) surveys provide information on the attitudes and behaviors of students on the use and abuse of substances such as alcohol, tobacco, and illicit and prescription drugs. The MTF study is designed so that changes in attitudes and behaviors can be observed across time.