Since independence, Algeria has made major technological advances, especially in the steel and petrochemical industries. However, Algeria still has a severe shortage of skilled workers and is heavily dependent on foreign technologies. Scientific training is principally conducted at the Hovari Boumedienne University of Sciences and Technology, founded at Algiers in 1974; the Oran University of Sciences and Technology, founded in 1975; the universities of Annaba (founded in 1975), Blida (founded in 1981), Boumerdes (founded in 1981), Constantine (founded in 1969), Oran Es-senia (founded in 1965), and Tlemcen (founded in 1974); and the Ferhat Abbas-Setif University of Setif (founded in 1978). In 1987–97, science and engineering students accounted for 58% of college and university enrollments. The government's National Bureau of Scientific Research operates 18 research centers in biology; anthropology; oceanography and Fisheries; astronomy, astrophysics, and geophysics; renewable energy; arid zones; technology transfer; and other fields.