Demographics or demographic data are selected population characteristics used in government such as race, age, income, disabilities, home ownership, employment status and travel time to work. Much of this data comes from the United States Census, the Census of Agriculture and the Economic Census. A census is a procedure for acquiring information about every individual in a society. In the United States a census is taken every ten years. Statistical data is supplemented by sampling in which information is only obtained from a subset of the population. In addition to playing its part in democracy, census data is commonly used in research, business marketing and planning., It is widely recognized that population and housing statistics gained through a census are necessary for the planning of any society.
Census tracts are small, relatively permanent statistical subdivisions of a county established by the United States Census Bureau. Usually tracts coincide with the limits of cities, towns or other administrative areas and several commonly exist within a county. Currently Delaware County is divided into 31 census tracts.