“In 2014, a total of 2.5 million persons aged ≥12 years had used marijuana for the first time during the preceding 12 months, an average of approximately 7,000 new users each day. During 2002–2014, the prevalence of marijuana use during the past month, past year, and daily or almost daily increased among persons aged ≥18 years, but not among those aged 12–17 years. Among persons aged ≥12 years, the prevalence of perceived great risk from smoking marijuana once or twice a week and once a month decreased and the prevalence of perceived no risk increased. The prevalence of past year marijuana dependence and abuse decreased, except among persons aged ≥26 years. Among persons aged ≥12 years, the percentage reporting that marijuana was fairly easy or very easy to obtain increased…

Since 2002, marijuana use in the United States has increased among persons aged ≥18 years, but not among those aged 12–17 years. A decrease in the perception of great risk from smoking marijuana combined with increases in the perception of availability (i.e., fairly easy or very easy to obtain marijuana) and fewer punitive legal penalties (e.g., no penalty) for the possession of marijuana for personal use might play a role in increased use among adults.”

Source: Azofeifa A, Mattson ME, Schauer G, McAfee T, Grant A, Lyerla R. National Estimates of Marijuana Use and Related Indicators — National Survey on Drug Use and Health, United States, 2002–2014. MMWR Surveill Summ 2016;65(No. SS-11):1–25. DOI: http://dx.doi.org/10.15585/mmwr.ss6511a1