The census occurs every 10 years- by constitutional law- and counts every resident of the United States. The data then goes to determine how much help communities receive for things like hospitals, schools and public work projects.
It also determines how many seats each state has in the U.S. House of Representatives.
The 10-question Census forms are mailed out to every residence in the U.S. and Puerto Rico during March. Residents should fill them out and then return them in the postage-paid envelope as quickly as possible.
Those who don't mail back the form might hear from census takers, who will go door-to-door visiting residents.