In the early 1990s, graduation from the compulsory education system occurred at aged sixteen. Eberstadt and Banister report that according to North Korean statistics released in the late 1980s, primary schools enrolled 1.49 million children in 1987; senior middle schools enrolled 2.66 million that same year. A comparison with the total number of children and youths in these age brackets shows that 96 percent of the age cohort is enrolled in the primary and secondary educational system.