Note: This table shows the following major trends: (1) for most age groupings, there is a steady growth in the percentage using illicit drugs from 1999 through 2001, (2) in 2001, there appears to be an increase over previous years in the percentage using illicit drugs, and (3) throughout the three time periods, the heaviest users of drugs (used in the past month and past year) are between 18 and 25 years of age. 

Note: these figures include use of marijuana, cocaine, hallucinogens, inhalants (except in 1982), heroin, and nonmedical use of sedatives, tranquil9izers, stimulants and analgesics. 

a Source of figures in this column: Substance Abuse and Mental Health Services Administration (SAMHSA), Office of Allied Studies (OAS). Preliminary Estimates from the 1995 National Household Survey on Drug Abuse, Rockville, MD: U.S. Department of Health and Human Services, August, 1996. 

b Source of figures in these two columns: SAMHSA. Summary of Findings from the 1998 National Household Survey on Drug Abuse. Rockville, MD: OAS and SAMHSA, 1999. 

c Source of figures in these two columns: SAMHSA. Summary of Findings from the National Household Survey on Drug Abuse, 1999 and 2000. Rockville, MD: OAS and SAMHSA, 2000. 

d Source of figures in this column: SAMHSA. Summary of Findings from the National Household Survey on Drug Abuse, 2000 and 2001. Rockville, MD: OAS and SAMHSA, 2002.