The prevalence of undernourishment refers to the proportion of the population with food consumption (based on food acquired by the household rather than food intake by individuals) below the minimum level of dietary energy consumption or the percentage of the population that is undernourished or food deprived. The prevalence of undernourishment are based on three key parameters for each country: the average amount of food available for human consumption per person, the level of inequality in access to that food and the minimum number of calories required for an average person. Average food available for human consumption is an estimate of how much of each food commodity a country produces, imports and withdraws from stocks for other non-food purposes. The energy equivalent of all the food available for human consumption is divided by the total population to come up with the average daily energy consumption. Data from household surveys are used to derive a coefficient of variation to account for the degree of inequality in access to food. Since, for instance, a large adult needs almost twice as much dietary energy as a three-year-old child, the minimum energy requirement per person for each country takes into account its mix of age, gender and body sizes.