http://www.oas.samhsa.gov/nhsda.htm
SAMHSA's National Survey on Drug Use & Health [formerly called the National Household Survey on Drug Abuse (NHSDA)] is the primary source of information on the prevalence, patterns, and consequences of alcohol, tobacco, and illegal drug use and abuse in the general U.S. civilian non institutionalized population, age 12 and older. It is currently conducted by SAMHSA's Office of Applied Studies (OAS).