demography

Study of the size, structure, dispersement, and development of human populations to establish reliable statistics on such factors as birth and death rates, marriages and divorces, life expectancy, and migration. Demography is used to calculate life tables, which give the life expectancy of members of the population by sex and age.

Demography is significant in the social sciences as the basis for industry and for government planning in such areas as education, housing, welfare, transport, and taxation. Demographic changes are important for many businesses. For example, the fall in the number of people aged 10–20 during the 1980s and the first half of the 1990s has led to many school closures, a shrinkage in the potential market for teenage clothes, and a fall in the number of young people available for recruitment into jobs by employers. Equally, the forecast rise in the number of people aged 75+ over the next 20 years will lead to an expansion of demand for accommodation for the elderly.

In March 1997, the National Institute of Aging's Office of the Demography of Aging reported that the quality of life of older US citizens had taken a historic turn for the better, with disabilities among the elderly declining 14.5% since 1982. Of 33.7 million elderly citizens in 1994, 7.1 million were disabled; scientists had predicted 8.3 million.