About 70% of Spain's student population attends public schools or universities. The remainder attends private schools or universities, the great majority of which are operated by the Catholic Church. Compulsory education begins with primary school or general basic education for ages 6-14. It is free in public schools and in many private schools, most of which receive government subsidies. Following graduation, students attend either a secondary school offering a general high school diploma or a school of professional education (corresponding to grades 9-12 in the United States) offering a vocational training program. The Spanish university system offers degree and post-graduate programs in all fields--law, sciences, humanities, and medicine--and the superior technical schools offer programs in engineering and architecture.