In 2018, 18.5 percent of the Kenyan adult population was illiterate, which was the highest rate of literacy in East Africa. There are very wide regional disparities: for example, Nairobi had the highest level of literacy at 87.1 per cent, compared to North Eastern Province, the lowest, at 8.0 per cent. Preschool, which targets children from age three to five, is an integral component of the education system and is a key requirement for admission to Standard One (First Grade). At the end of primary education, pupils sit the Kenya Certificate of Primary Education (KCPE), which determines those who proceed to secondary school or vocational training. The result of this examination is needed for placement at secondary school.