In Belarus education is compulsory for 10 years, from ages 7 to 17. Primary school, generally starting at age 7 and lasting for 5 years, is followed by an additional 5 years of secondary school. These schools fall into three categories: general, teacher training, and vocational. Institutions of higher education include three universities, four polytechnical institutes, and a number of colleges specializing in agricultural or technical sciences. In early 1992, some 61 % of eligible children attended preschool institutions in Belarus. During the 1993-94 school year, Belarus had 1.5 million children in 5,190 primary and secondary schools, 175,450 students in 33 institutions of higher education, and 129,000 students in 148 technical colleges. The literacy rate was 100 %, and the population was fairly well educated. While the current literacy rate is high, only about 30 % of the population was literate in 1919. The Soviet regime emphasized compulsory education and claimed to have eliminated illiteracy by the 1950s. At the same time, after the 1920s there was little provision for education in the Belarusian language. In the post-World War II years, and particularly in the 1960s and 1970s, the culture of the republic was thoroughly Russified through government policies that emphasized the Russian language. Schools that taught in the Belarusian language were closed, primarily in rural areas. The process of Russification was reversed somewhat between 1984 and 1990, when Mikhail Gorbachev was leader of the USSR, and in the early 1990s.