Each year the National Center for Education statistics gives an account of the state of education in the United States. This year's report showed that overall private school enrollment remained at 10% for elementary and secondary schools. Catholic schools continue to maintain the largest share of total private school enrollment, at 40 percent. Over a ten-year period, from the 2001-2002 school year to the 2011-2012 school year, the number of private school students in pre-kindergarten through grade 12 decreased by one million. In contrast, the number of private school children in grades 9 through 12 increased from 1.2 million to 1.3 million.
The complete report and accompanying data tables can be found at:http://nces.ed.gov/programs/coe/current_tables.asp.