The U.S. Census counts every resident in the United States. It is mandated by Article I, Section 2 of the Constitution and takes place every 10 years. The data collected by the decennial census determine the number of seats each state has in the U.S. House of Representatives and is also used to distribute billions in federal funds to local communities. Additional Information can be found at Through the Decades.
QUESTIONS
Over the years, Congress has authorized additional questions, enabling us to better understand the nation's inhabitants and their activities and needs. Through the decades, the census has collected data on race, ancestry, education, health, housing, and transportation. An examination of the questions asked during each census illustrates changes in our nation's understanding of race, the impact of immigration, growth of the Hispanic population, and computer usage. Visit the web site: Index of Questions for lists of the questions asked during each census.
QUESTIONNAIRES
Between 1970 and 2000, the U.S. Census Bureau used two questionnaires. Most households received a short-form questionnaire asking a minimum number of questions. A sample of households received a long-form questionnaire that included additional questions about the household.
The 2010 Census had just one questionnaire consisting of ten questions. (Read more about Questionnaires from 1790 to 2010.)