It seems only about a third of the US population takes SAT. I couldn't get the actual size of the 18-year-old cohort from US Census [1], but from various age g

It seems only about a third of the US population takes SAT. I couldn't get the actual size of the 18-year-old cohort from US Census [1], but from various age groups it could be estimated to be ~4-5M, while SAT was taken by ~1.5M people in 2009 [2]. This would also roughly fit with 27% of the population which got bachelor degree or higher [3]. [1] http://factfinder.census.gov/servlet/STTable?_bm=y&-qr_name=ACS_2008_1YR_G00_S0101&-geo_id=01000US&-ds_name=ACS_2008_1YR_G00_&-_lang=en&-redoLog=false&-state=st http://factfinder.census.gov/servlet/STTable?_bm=y&-qr_n... [2] http://professionals.collegeboard.com/profdownload/cbs-2009-national-TOTAL-GROUP.pdf http://professionals.collegeboard.com/profdownload/cbs-2009-... [3] http://factfinder.census.gov/servlet/STTable?_bm=y&-geo_id=01000US&-qr_name=ACS_2006_EST_G00_S1501&-ds_name=ACS_2006_EST_G00_&-redoLog=false http://factfinder.census.gov/servlet/STTable?_bm=y&-geo_...