Charter schools are publicly funded schools that have more autonomy than traditional public schools in exchange for accountability for student performance. The first charter school law was passed in Minnesota in 1991, and now 41 states have laws allowing charter schools. Charter schools operate independently but are accountable for student achievement. Around 12.5% of charter schools have closed for not meeting performance standards. Charter schools receive less public funding per student on average than traditional public schools, but can supplement this funding through private donations. Research shows charter school students, particularly white males with educated parents, tend to perform better in math and reading than students in traditional public schools.