“Gross” enrollment includes students of all ages, including students whose age is different from the official age group. When there is late enrollment, early enrollment, or grade repetition, the total student enrollment can exceed the population of the age group that officially corresponds to the level of education – leading to ratios greater than 100 percent.
“Net” enrollment includes only children of the official school age, as defined by the national education system. Small discrepancies in the reported age of children may occasionally cause net enrollment rates to exceed 100 percent.
Since the net enrollment rate excludes overage and underage students, it more accurately captures an education system’s coverage and internal efficiency than gross enrollment ratio. However, it is useful to see differences between the gross enrollment ratio and the net enrollment rate for capturing the incidence of overage and underage enrollments.
The majority of high-income countries have a literacy rate of more than 95%. The World Bank literacy data from UNESCO includes data for some high-income countries like Singapore, however, does not include data for OECD members.