Introduction to Census
The first census was conducted in 1790 and counted 3.9 million people. Then the census was taken in the 13 original states, plus the districts of Kentucky, Maine, Vermont, and the Southwest Territory (of Tennessee). Federal Marshalls asked six questions: name of head of family and number of persons in household, and the number of persons in each household of the following descriptions: Free White males 16 years and upward, free White males under 16 years, free White females, all other free persons (by sex and color) and slaves.
Census 2000, taken April 1, 2000, counted 281,421,906 people in the 50 states and the District of Columbia. The questionnaire included seven questions for each household: name, sex, age, relationship, Hispanic origin, race, and whether the housing unit was owned or rented. In addition to these seven questions, about 17 percent of the households got a much longer questionnaire including questions about ancestry, income, mortgage, and size of the housing unit. Census 2000 not only counted the population, but also sampled the socio-economic status of the population, providing a tool for government, educators, business owners, and others to get a snapshot of the state of the nation.
The U.S. Constitution, Article I, Section 2 mandates that an apportionment of representatives among the states, for the House of Representatives, be carried out every ten years (decennially). Apportionment is the process of dividing the 435 seats in the US House of Representatives among the 50 states. Congress decides the method to carry out the apportionment and, since 1940, has used the method of ‘equal proportions’ in accordance with Title 2, US Code.
Using equal portions, each state is assigned one congressional seat (as provided by the Constitution). The apportionment formula then allocates the remaining 385 seats one at a time among the 50 states until all 435 seats are assigned.
In addition to apportionment, the decennial census results are used to:
distribute almost $200 billion annually in Federal and state, local, and tribal funds;
draw state legislative districts;
evaluate the success of programs or identify populations in need of services;
and many other purposes. Visit this site for a comprehensive review of each of the questions and why it is asked.