The 1991 survey is the 11th in a series that began in 1971. It covers the population age 12 and over living in all 50 States. Results are based on personal interviews combined with self-administered questionnaires from 32,594 participants who are randomly selected from the household population. Populations of six major metropolitan areas are oversampled. Persons living in dormitories and homeless shelters and civilians on military institutions were included in the 1991 survey for the first time, although the survey did not include transient populations such as the homeless not in shelters. The survey covered three major age groups: youth ages 12-17, young adults ages 18-25, and older adults ages 26 and over. Tables