Statistics Iceland collects annual data on students, staff and school operation in pre-primary schools, compulsory schools, upper secondary schools, colleges and universities. In most cases the data are collected directly from the schools. In 1997 Statistics Iceland began a data collection on pre-primary schools and compulsory schools. Statistics on upper secondary and tertiary level are available from 1975 and since 1995 data have also been gathered on graduates in upper secondary and tertiary level education. In 1998 the collection of data on the personnel and operation of upper secondary schools, colleges and universities was started.