Twenty-seven percent of the estimated 564,743 gay couples in the United States reported themselves as married in 2008, according to the first U.S. Census figures on same-sex marriage provided to the Associated Press.

While the U.S. Census Bureau estimates that approximately 100,000 legal same-sex marriages, civil unions, and domestic partnerships were entered last year, nearly 150,000 same-sex couples reported being in a spousal relationship.

Analysts suggest that the figure disparities are a reflection of same-sex couples in committed relationships who would get married if they could in their states. During all or part of 2008, same-sex marriage was legal in California, Connecticut, and Massachusetts, while only a handful of other states recognized civil unions and domestic partnerships.

The statistics come as the U.S. Census Bureau prepares to make an official count of same-sex marriages, civil unions, and domestic partnerships for the first time in the 2010 Census. Gay advocacy groups expect to turn up several statistics supporting needs for federal reform on gay rights concerning issues like employment protection, adoption, and marriage.