"In the thirteen-year (2004–2016) combined sample of young adults aged 21–30, 1.5% report having ever used any drug by injection not under a doctor’s orders, and 0.5% reported doing so on 40 or more occasions (Table 4-1a). Thus, about 1 in every 67 respondents has ever used an illicit drug by injection, and about 1 in every 200 respondents reports an extended pattern of use as indicated by use on 40 or more occasions. There is a fair-sized gender difference -- 2.3% of males vs. 0.9% of females indicate ever injecting a drug.
"Marijuana, the most widely used of the illicit drugs, did not show any significant change in annual prevalence this year in any of the three grades, nor in the three grades combined. After rising for several years, the annual prevalence of marijuana has more or less leveled out since about 2010.
"During the 1990s, the annual prevalence of marijuana use tripled among 8th graders (from 6% in 1991 to 18% in 1996), more than doubled among 10th graders (from 15% in 1992 to 35% in 1997), and nearly doubled among 12th graders (from 22% in 1992 to 39% in 1997). Among college students, however, the increase in marijuana use was much more gradual, presumably due to a generational replacement effect. Annual prevalence of use rose by about one third, from 27% in 1991 to 36% in 1998.
"Annual marijuana prevalence peaked among 12th graders in 1979 at 51%, following a rise that began during the 1960s. Then use declined fairly steadily for 13 years, bottoming at 22% in 1992—a decline of more than half. The 1990s, however, saw a resurgence of use. After a considerable increase (one that actually began among 8th graders a year earlier than among 10th and 12th graders), annual prevalence rates peaked in 1996 at 8th grade and in 1997 at 10th and 12th grades. After these peak years, use declined among all three grades through 2007 or 2008.
Estimated 30-Day Prevalence of Use of Various Drugs for Grades 8, 10, and 12 Combined in the US, 1998-2016 - Entries are Percentages
"Crack cocaine use spread rapidly from the early to mid-1980s. Still, among 12th graders, the use of crack remained relatively low during this period (3.9% annual prevalence in 1987). Clearly, crack had quickly attained a reputation as a dangerous drug, and by the time of our first measurement of perceived risk in 1987, it was seen as the most dangerous of all drugs. Annual prevalence dropped sharply in the next few years, reaching 1.5% by 1991, where it remained through 1993.