Does the US Census Bureau send out questionnaires to random residents after completing one?

I received a random questionnaire last month from the Census Bureau. (Dec 2011). It was very detailed and intrusive- I only answered about 1/4 of the questions. They have since called me and want the Omissions completed. This is way beyond number in household questions- they want education, salary info, insurance coverage info, languages spoken-. I'm offended and think this is a violation of privacy.