For the year 2000, adult illiteracy was estimated at 0.5% (males, 0.3%; females, 0.6%). Education is free and compulsory for all children between the ages of 7 and 15 years (for 9 years). While Lithuanian is the most common medium of instruction, children also study Polish, Russian, and Yiddish. In 1997, primary schools enrolled 225,701 students and employed 14,095 teachers. Student-to-teacher ratio stood at 16 to one. At the secondary level in the same year, there were 378,754 students and 36,932 teachers. As of 1999, 94% of primary-school-age children were enrolled in school, while 88% of those eligible attended secondary school.
Postsecondary institutions had 13,136 teachers and a total student body of 83,645 in 1997. The four known universities are: Kaunas University of Technology (founded in 1950); Vilnius Technical University (founded in 1961); Vilnius University (founded in 1579); and Vytautas Magnus University (founded in 1922). Approximately 22.8% of the government's annual budget was allocated to education in the latter part of the 1990s. As of 1999, public expenditure on education was estimated at 6.4% of GDP.