Prevalence and Perceived Risk From Marijuana Use Among Young People in the US
"Marijuana use, which had been rising among teens for the past four years, continued to rise in 2011 in all prevalence periods for 10th and 12th graders; but in 2012 these increases halted. The recent rise in use stood in stark contrast to the long, gradual decline that had been occurring over the preceding decade. (Although use among 8th graders had been rising, annual prevalence decreased after 2010.) It is relevant that perceived risk for marijuana has been falling for the past six years, and disapproval declined for the past three to four years. These changes would normally portend a further increase in use."
Johnston, L. D., O’Malley, P. M., Bachman, J. G., & Schulenberg, J. E. (2013). Monitoring the Future national results on adolescent drug use: Overview of key findings, 2012. Ann Arbor: Institute for Social Research, The University of Michigan, p. 5.