 64,000 units (3,000,000 m2 (32,000,000 sq ft)) of this type were built in Moscow from 1961 to 1968.In Moscow, space limitations forced a switch to 9 or 12-story buildings; the last 5-story Khrushyovka was completed there during 1971.The rest of the USSR continued building Khrushyovkas until the fall of the Soviet Union; millions of such units are now past their design lifetime.