For the year 2000, adult illiteracy was estimated at 0.6% (males, 0.2%; females, 0.8%). Education, mostly free and state funded, is also compulsory for nine years. In 1999 approximately 93% of primary-school-age children were enrolled in school. The state also provides a stipend for higher education. Although Russian is the most common medium of instruction, other languages are also taught, especially at the secondary level. In the early 1990s, many privately owned institutions were opened, and the education system was modified with the introduction of a revised curriculum. In 1995, 7,849,000 students were enrolled in 66,235 primary schools, with 395,000 teachers. Secondary schools had a total enrollment of 13,732,000 students. The pupil-teacher ratio at the primary level was 19 to 1 in 1999. As of 1999, public expenditure on education was 3.6% of GDP.
At the tertiary level, there were 382,897 teachers and 4,458,363 students in 1995. Approximately 56% of these students were female. The St. Petersburg State University, which was founded in 1724, is well known for its education.