Here's what MTF had to say about teen marijuana use:
"Annual marijuana prevalence peaked among 12th graders in 1979 at 51%, following a rise that began during the 1960s. Then use declined fairly steadily for 13 years, bottoming at 22% in 1992 -- a decline of more than half. The 1990s, however, saw a resurgence of use. After a considerable increase (one that actually began among 8th graders a year earlier than among 10th and 12th graders), annual prevalence rates peaked in 1996 at 8th grade and in 1997 at 10th and 12th grades. After these peak years, use declined among all three grades through 2006, 2007, or 2008; after the declines, there began an upturn in use in all three grades, lasting for three years in the lower grades and longer in grade 12. In 2011 and 2012 there was some decline in use in grade 8, with 10th and 12th grades leveling in 2012. In 2010 a significant increase in daily use occurred in all three grades, followed by a nonsignificant increase in 2011. In 2012 there were non-significant declines for daily use in the lower grades and a leveling at 12th grade with use reaching 1.1%, 3.5%, and 6.5% in grades 8, 10, and 12, respectively."
The bolding is ours. There are short term ups and downs, but they seem to be of mainly rhetorical and polemical significance.
If you look at the handy tables at the end of the report, you see that combined lifetime marijuana use for all three grades (8, 10, and 12), was at 30.7% last year, about the same as it was in 1995 (31.6%) or 2005 (30.8%). Much happens, but little changes.
Ditto for annual use: 26.1% in 1995, 23.4% in 2005, 24.7% last year.
Ditto for monthly use: 15.6% in 1995, 13.4% in 2005, 15.1% last year.
Ditto for daily use: 2.7% in 1995, 2.9% in 2005, 3.6% last year.
The daily use figures could be alarming ("Daily Teen Pot Smokers Up 25% Since 1995"), except the trend-line is not steadily upward, but varies from year to year (it was 3.7% in in 2001 and 2.7% in 2007).
Look for some terrifying spin about how the numbers show the kids are going to pot. But when you look at the numbers more closely and over time, when it comes to teens and marijuana, meh, what's new?