This Alberta Official Statistic compares the total dependency ratio, the youth dependency ratio and the old age dependency ratio for the eight economic regions in Alberta for 2011. Dependency ratio (age dependency ratio) is the ratio of persons in the "dependent" ages (generally under age 15 and over age 64) to those in the "economically productive" ages (15 - 64 years) in a population. The age-dependency ratio is sometimes divided into old-age dependency (the ratio of people ages 65 and older to those ages 15-64) and child-dependency (the ratio of people under age 15 to those ages 15-64) ratios. The sum of these two is the total (age) dependency ratio. The age-dependency ratio is often used as an indicator of the economic burden the productive portion of a population must carry - even though some persons defined as "dependent" are producers and some persons in the "productive" ages are economically dependent. Countries with very high birth rates usually have higher dependency ratios because of the large proportion of children in the population.