Age of riches: Elite prep schools with college size endowments

Average expenditures per student for public schools, not adjusted for inflation, rose 28 percent, to $8,809, between the 1999 and 2004 fiscal years, according to the National Center for Education Statistics.

That compares with a 40 percent increase, to $20,233, for independent secondary day schools, and a 42.8 percent increase, to $14,300, for each elementary student at day schools. Spending by boarding schools rose 24 percent, to $37,566, in the five years that ended June 30, 2005.