Secondary completion rate is the total number of graduates from the last grade of secondary education, regardless of age, expressed as a percentage of the population of the age group that officially corresponds to that of graduating from secondary schools
Primary completion rate is the percentage of students completing the last year of primary school. The UN defines it as: the total number of new entrants in the last grade of primary education, regardless of age, expressed as percentage of the total population of the theoretical entrance age to the last grade of primary. The ratio can exceed 100% due to over-aged and under-aged children who enter primary school late / early and / or repeat grades
Net enrolment rate is the number of children of official school age (based on the International Standard Classification of Education 1997) who are enrolled in school as a percentage of the population of the corresponding official school age