secondary school. At the end of the secondary stage, GCE 'O' Level exams are taken; at the end of the following pre-university stage, the GCE 'A' Level exams are taken. Of all non-student Singaporeans aged 15 and above, 18% have no educational qualifications at all while 45% have the Primary School Leaving Examination as their highest qualification. 15% have the GCE 'O' Level as their highest qualification and 14% have a degree.
Singaporean students consistently rank top five in the world in the two major international assessments of mathematics and science knowledge. Singaporean students were ranked first in the latest Trends in International Mathematics and Science Study conducted by the International Association for the Evaluation of Educational Achievement and have been ranked top three every year since 1995. Singaporean students were also ranked top five in the world in terms of mathematics, science and reading in the 2009 Programme for International Student Assessment conducted by the OECD. The country's two main public universities – the National University of Singapore and Nanyang Technological University – are among the top 100 universities in the world