The figure is a line graph titled “Long-Term Trends in Annual Marijuana Use Among 8th-, 10th-, and 12th-graders.” The y-axis is labeled “Percent” and ranges from 10 to 40; the x-axis shows years from 1996 through 2011. Blue, gold, and green lines show use of marijuana in the past 12 months by 8th-graders, 10th-graders, and 12th-graders, respectively—in all cases generally dropping from late 1990s to the late 2000s, then increasing. The blue line shows a decline from 18.3 percent in 1996 to 10.3 percent in 2007, and then a slight increase thereafter, ending at 12.5 percent in 2011. The gold line for 10th-graders starts at 33.6 percent in 1996, generally declines to 23.9 percent in 2008 and then increases to 28.8 percent in 2011. The green line for 12th graders starts at 35.8 percent in 1996 and hovers around 37-38 percent until 2001, when it begins a gradual decline to 31.5 percent in 2006, at which point the trend reverses, climbing to 36.4 percent in 2011. The source of the data in the graph is the University of Michigan, 2011 Monitoring the Future Study.