"In 2002 and 2003, an estimated 88.2 percent of persons aged 21 or older (175.6 million) were lifetime alcohol users, whereas an estimated 11.8 percent (23.5 million) were lifetime nondrinkers. Over half of lifetime alcohol users (52.7 percent) had used one or more illicit drugs at some time in their life, compared to 8.0 percent of lifetime nondrinkers. Among persons who had used an illicit drug in their lifetime, the average age at first illicit drug use was 19 years for lifetime alcohol users, versus 23 years for lifetime nondrinkers."


"Illicit Drug Use Among Lifetime Nondrinkers and Lifetime Alcohol Users," Office of Applied Programs, Substance Abuse & Mental Health Services Administration, US Dept. of Health and Human Services, June 14, 2005, p. 2.