Enrolment of the official age group for a given level of education either at that level or the levels above, expressed as a percentage of the population in that age group.
The adjusted net enrolment ratio for lower secondary school age adolescents is a second-best indicator which has information on trends for just 82 countries (UNESCO, 2014: 67).
UNESCO. 2014. Teaching and Learning: Achieving Quality for All; EFA Global Monitoring Report, 2013-2014. Paris: UNESCO.