Decennial Census Data on Same Sex Couples
The Decennial Census occurs every 10 years, in years ending in zero, to count the population and housing units for the entire United States. Its primary purpose is to provide the population counts that determine how seats in the U.S. House of Representatives are apportioned.
Data about same sex couples are available for the U.S., 50 states and the District of Columbia, counties, and subcounty statistical areas (such as zip codes and block groups) from 1990 to the present.