Figure 9.

Percentage of revenue for public elementary and secondary schools, by source of funds: 1970–71 through 2006–07

SOURCE: U.S. Department of Education, National Center for Education Statistics, Revenues and Expenditures for Public Elementary and Secondary Education, 1970–71 through 1986–87; and Common Core of Data (CCD), "National Public Education Financial Survey," 1987–88 through 2006–07.