Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Initiation of smoking among 12- to 17-year-old adolescents in the United States by sex, 1940–2000. All calculations to determine the year in which respondents began smoking were based on the survey administration date in conjunction with responses given in the survey regarding initiation age of “regular” use and current age. Data are from the Tobacco Use Supplements to the Current Population Survey (25,26). Means and 95% confidence intervals (error bars) are shown.
