The continuing influx of rural people to towns and cities, coupled with the rise in levels of expectation among the urban population, has created a serious housing problem; improvement in urban housing is one of Sa'udi Arabia's foremost economic needs. Some 506,800 dwelling units were built during 1974–85, 389,000 by the private sector, with the help of the Real Estate Development Fund, and 117,800 by the Deputy Ministry of Housing and other government agencies. In 1984, 78,884 building permits were issued, 84% of these for concrete dwellings and 8% for housing units of blocks and bricks. In the oil districts, ARAMCO, through loans and other assistance, has encouraged construction of private homes and has built accommodations for its unmarried Sa'udi staff members. The Real Estate Development Fund, established in 1975, continues to provide interest-free loans for home construction by individuals as well as private companies.