Vocational secondary education encompassed the largest number of schools and was reported to enroll almost 50 percent of all secondary school students. These schools provided a one- or two-year program of combined general education and vocational training in all the trades necessary for the national economy. Vocational schools were usually organized at the locations of industrial enterprises and socialist cooperatives, and students were trained as skilled workers. Additional vocational training was also provided in the form of apprentice or on-the-job training to workers already employed in industrial installations. The bulk of these trainees had either completed the compulsory level of education and then dropped out of school or had failed to be selected in the competitive examination for entrance into secondary school. Vocational training had not kept pace with increasing industrialization, and in 1972 the demand for trained workers continued to surpass the supply (see ch. 16). Higher Education The system of higher education was comprised primarily of universities and polytechnical and specialized institutes, which in 1971 had a total enrollment of approximately 150,000 students. All institutions were under the direct supervision of the Ministry of Education and were geared to produce specialists in the humanities, in the social, natural, physical, and engineering sciences, and in education as needed to fill positions in government and all sectors of the economy. The schools of higher learning were generally headed by a rector (university) or a director (technical institute), who was appointed by the Ministry of Education for a period of four years. Schools were divided into faculties, headed by deans; faculties, in turn, were divided into departments, each headed by a chairman. Collectively the rector, deans, chairmen, and certain other selected faculty members were grouped into an advisory council, which had broad authority in carrying out the government's educational policies, approving the faculty work programs, supervising the instruction carried out by the departments, and granting degrees at the graduate level. Students were admitted to all higher schools on the basis of competitive examination and assigned to particular faculties according to government-directed areas of study. Most degree courses at universities required three to six years to complete, and those at polytechnical institutes, from two to three years. Medical and dental degrees were granted at institutes attached to universities and required six years of study.