The College Board, “AP Program Participation and Performance Data 2015,” https://research.collegeboard.org/programs/ap/data/participation/ap-2015
; and The College Board, “AP Data—Archived Data,” http://research.collegeboard.org/programs/ap/data/archived
. Student counts used to calculate the rate of exam-taking: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, “Digest of Education Statistics 2015” (online version), Table 105.30, https://nces.ed.gov/programs/digest/d15/tables/dt15_105.30.asp
, accessed 7/12/2016.