A greater percentage of high-poverty public schools than low-poverty public schools were charter schools. A charter school is a school that provides free public education to students under a specific charter granted by the state legislature or other appropriate authority. At the elementary level, 5 percent of high-poverty and 3 percent of low-poverty schools were charter schools (see table A-24-2). Ten percent of high-poverty public secondary schools were charter schools, compared with 3 percent of low-poverty schools. From 1999–2000 to 2007–08, the percentage of charter schools that were high-poverty increased from 13 to 23 percent, while the percentage that were low-poverty declined from 37 to 21 percent (see table A-32-1).