Food and Agriculture Organization of the United Nations (FAO). 2013. FAOSTAT Online Statistical Service. Rome: FAO. Available online at: http://www.fao.org/economic/ess/ess-fs/ess-fadata/en/
Population undernourished is the percentage of a country's population that consistently has a food intake that is less than a minimum dietary energy consumption required for maintaining health and performing light physical activity. This requirement varies by country, and is calculated by looking at the amount of food available in a country and a measure of inequality in distribution developed using household income and expenditure surveys. The minimum requirement for dietary energy is usually between 1750 and 2030 kilocalories per person per day. The data is expressed as a country's average over a 3-year period.