I was a Crew Leader Assistant, during the last Census – if you don’t answer the questions, someone will be knocking at your door to try and get you to answer the questions.
It is illegal for the answers to be used for anything but finding out how many people live in a certain area, their ages, income and their race (if you choose to disclose that information) You don’t have to answer every question, the form will tell you which are mandatory and which are optional.
The information gathered helps determine how many seats your state will have in the House of Representatives and how much money will go to you local school districts, senior services, emergency services, etc…
If helping your local community is not a good enough reason, you should also know it’s required by law to answer the census.