15% of U.S. graduates in 2008 passed at least one AP exam
Overall participation in AP tests has increased over the past 10 years, and 2008 data shows that six states reported that at least one-fifth of their graduates passed at least one AP exam, including California. Participation in AP has exploded this decade. Educators have embraced it as a sort of national curriculum for high school students who are ready for college study.
AP report to the nation. (2009). New York: College Board.