"Marijuana, the most widely used of the illicit drugs, did not show any significant change in annual prevalence this year in any of the three grades, nor in the three grades combined. After rising for several years, the annual prevalence of marijuana has more or less leveled out since about 2010.
"This year, 12 percent of 8th graders, 25 percent of 10th graders and 35 percent of 12th graders reported using marijuana at least once in the prior 12 months. Of more importance, perhaps, is their daily or near-daily marijuana use (defined as smoking marijuana on 20 or more occasions in the past 30 days). These rates stand at 1.1 percent, 3.0 percent and 6.0 percent in 8th, 10th and 12th grades, respectively.
"In other words, one in every 16 or 17 high school seniors is smoking marijuana daily or near daily. These rates have changed rather little since 2010, but are from three-to-six times higher than they were at their low point in 1991.
"'The proportion of our young people smoking marijuana this frequently remains a matter of concern,' Johnston said.,
"He notes that the percent of students who see regular marijuana use as carrying a great risk of harm has declined substantially since about 2005, and is still declining. Over the past 10 years, the percent seeing a great risk in regular marijuana use has fallen among 8th graders from 74 percent to 58 percent, among 10th graders from 66 percent to 43 percent and among 12thgraders from 58 percent to 32 percent."
Johnston, L. D., O'Malley, P. M., Miech, R.A., Bachman, J. G., & Schulenberg, J. E. December 16, 2015. Use of ecstasy, heroin, synthetic marijuana, alcohol, cigarettes declined among US teens in 2015. University of Michigan News Service: Ann Arbor, MI.