Monitoring the Future national survey results on drug use, 1975-2018: Overview, key findings on adolescent drug use

Annual marijuana prevalence rose by a nonsignificant 0.5 percentage points to 23.9% in 2018 based on data from the three grades combined. 2 This follows a significant increase in 2017. Annual prevalence stands at 11%, 28%, and 36% in grades 8, 10, and 12. Daily marijuana prevalence changed little this year, with rates at 1%, 3%, and 6%, respectively. Annual use of any illicit drug, which tends to be driven by marijuana-by far the most prevalent of the illicit drugs-also rose nonsignificantly in grades 8 and 10, but declined nonsignificantly in 12 th grade. Change in 2018 for the three grades combined also did not reach significance. Since 2006 there has been rather little systematic change in this index.