In the 1988–89 school year, 301 students per 10,000 population were in specialized secondary or higher education, a figure slightly lower than the Soviet average. In 1989 some 58% of Armenians over age fifteen had completed their secondary education, and 14% had a higher education. In the 1990–91 school year, the estimated 1,307 primary and secondary schools were attended by 608,800 students. Another seventy specialized secondary institutions had 45,900 students, and 68,400 students were enrolled in a total of ten postsecondary institutions that included universities. In addition, 35% of eligible children attended preschools. In 1992 Armenia's largest institution of higher learning, Yerevan State University, had eighteen departments, including ones for social sciences, sciences, and law. Its faculty numbered about 1,300 teachers and its student population about 10,000 students. The National Polytechnic University of Armenia is operating since 1933.