Life expectancy (years)

Expected years of schooling?Expected years of schooling is a calculation of the number of years a child of school entrance age is expected to spend at school, or university, including years spent on repetition. It is the sum of the age-specific enrolment ratios for primary, secondary, post-secondary non-tertiary and tertiary education and is calculated assuming the prevailing patterns of age-specific enrolment rates were to stay the same throughout the child’s life. Expected years of schooling is capped at 18 years.
Source: UNESCO Institute for Statistics (2010). Correspondence on education indicators. March. Montreal.

Mean years of schooling?Mean years of schooling (of adults) (years) is a calculation of the average number of years of education received by people ages 25 and older in their lifetime based on education attainment levels of the population converted into years of schooling based on theoretical durations of each level of education attended.
Source: Barro, R. J.; Lee, J.-W. (2010). "A New Data Set of Educational Attainment in the World, 1950–2010". NBER Working Paper No. 15902.

Gross national income per capita (US Dollar)?GNI per capita based on purchasing power parity (PPP). PPP GNI is gross national income (GNI) converted to international dollars using purchasing power parity rates. An international dollar has the same purchasing power over GNI as a U.S. dollar has in the United States. GNI is the sum of value added by all resident producers plus any product taxes (less subsidies) not included in the valuation of output plus net receipts of primary income (compensation of employees and property income) from abroad.
Source: The World Bank