special schools grew fivefold between 1960 and 1980. However, the availability of such special schools varied greatly from one republic to another. On a per capita basis, such special schools were most available in the Baltic republics, and least in the Central Asian ones. This difference probably had more to do with the availability of resources than with the relative need for the services by children in the two regions. In the 1970s and 1980s, approximately 99.7% of Soviet people were literate. Classification and terms The Soviet educational system was organized into three levels. The names of these levels were and are still used to rate the education standards of persons or particular schools, despite differences in the exact terminology used by each profession or school. Military, militsiya, KGB and Party schools were also graded according to these levels. This distinguishes the Soviet system from the rest of the world, where educational levels of schools may differ, despite their similar names. Elementary schools were called the "beginning" level (, nachalnoye), 4 and later 3 classes. Secondary schools were 7 and later 8 classes (required complete elementary school) and called "incomplete secondary education" (, nepolnoye sredneye obrazavaniye). This level was compulsory for all children (since 1958-1963) and optional for under-educated adults (who could study in so-called "evening schools"). Since 1981, the "complete secondary education" level (10 or, in some republics, 11 years) was compulsory. 10 classes (11 classes in the Baltic republics) of an ordinary school was called "secondary education" (—literally, "middle education"). PTUs, tekhnikums, and some military facilities formed a system of so-called “secondary specialized education” (, sredneye spetsialnoye). PTU's were vocational schools and trained students in a wide variety of skills ranging from mechanic to hairdresser. Completion of a PTU after primary school did not provide a full secondary diploma or a route to such a diploma. However, entry to a tekhnikum or other specialized secondary school could be started after either 8 or 10 classes of combined education in elementary and secondary school. Graduation from this level was required for the positions of qualified workers, technicians and lower bureaucrats (see also vocational education, professions, training). “Higher” (, vyssheye) educational institutions included degree-level facilities: universities, “institutes” and military academies. "Institute" in the sense of a school refers to a specialized "microuniversity" (mostly technical), usually subordinate to the ministry associated with their field of study. The largest network "institutes" were