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. Author manuscript; available in PMC: 2018 May 1.
Published in final edited form as: Drug Alcohol Depend. 2017 Mar 7;174:150–157. doi: 10.1016/j.drugalcdep.2017.01.025

Table 3B.

Age at first opportunity, among all participants (weighted for sampling design, Nwt=3,285)

Marijuana Inhalants Hallucinogens Cocaine Meth Heroin Stimulants Analgesics Tranquilizers Ecstasy

%wt <15 17.7 2.6 1.8 0.4 1.0 0.1 1.5 0.9 0.7 1.9
%wt 15 to 17 49.6 7.2 17.8 8.8 7.3 1.4 17.1 17.0 8.9 14.9
%wt 18 to 21 19.8 10.6 27.1 25.8 10.9 3.8 42.9 23.5 13.7 20.1
%wt 22 or older 3.0 3.1 4.9 7.7 3.0 0.7 4.0 5.8 7.9 5.9
%wt Never 9.8 76.5 48.4 57.2 77.8 94.0 34.5 52.8 68.8 57.2
Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0

Note. Data on amphetamines and methamphetamines were combined under “meth” to reflect the earliest age at which participants had the opportunity to use either drug. Stimulants, analgesics, and tranquilizers were opportunity for nonmedical use only; does not include medically supervised use. For tabulating weighted results in Table 3B among the overall sample, missing follow-up data were treated as no opportunity; therefore, results represent minimum estimates.