Because the Soviet Union had not built enough schools to accommodate increasing enrollment, Russia inherited a system of very large, overcrowded schools with a decaying infrastructure. By the late 1980s, 21 percent of students were attending schools with no central heating, and 30 percent were learning in buildings with no running water. In 1992 Russia had nearly 67,000 primary and secondary schools, which provided an average per-pupil space of 2.6 square meters, one-third the official standard. About one-quarter of schools housed 900 or more students. In 1993 Russia was forced to close about 20,000 of its schools because of physical inadequacy, and an estimated one-third of the national school capacity was in need of large-scale repair. In 1994 one of every two students attended a school operating on two or three shifts. Rural schools, which make up about 75 percent of the national total, were in especially bad condition.