Number of persons aged 12 to 17 who refrained from marijuana use in the past year
Number of persons aged 12 to 17 who never used marijuana in their lives prior to the past year
From the 2008 National Survey on Drug Use and Health:
How old were you the first time you used marijuana or hashish?
Klein, R.J.; Proctor, S.E.; Boudreault, M.A.; Turczyn, K.M. Healthy People 2010 Criteria for Data Suppression. Statistical Notes No. 24. Hyattsville, MD: National Center for Health Statistics. 2002.
Substance Abuse and Mental Health Services Administration. Results from the 2008 National Survey on Drug Use and Health: National Findings. Office of Applied Studies, NSDUH Series H-36, HHS Publication No. SMA 09-4434. Rockville, MD. 2009.