The ratio between the number of people in a population between the ages of 15 and 64 and the dependent population: children (0–14) and elderly people (65 and over). It is used as a rough way of quantifying the ratio between the economically active population and those they must support, but the age limits are somewhat arbitrary as, in the UK, for example, 30% of over-16-year-olds go on to higher education, and are therefore still dependent, either on the state or, increasingly, on their parents or bank managers.