In California, 28,312 same-sex couples say they are married, more than in any other state, according to numbers released Tuesday by the U.S. Census Bureau.
The new data marks the first time the agency has published information about same-sex spouses.
California also has the highest number of same-sex couples overall, at 98,153. Gay and lesbian couples comprise .78 percent of the state's households. Only the District of Columbia, Vermont and Massachusetts — where same-sex marriages are legal — have a higher percentage of same-sex households.
Nationwide, there are 646,464 same-sex couples, 131,729 of whom are married.
The number of same-sex couples in the United States has grown by 80 percent in the past decade, from 358,390 in 2000. Since then, six states plus the District of Columbia have legalized same-sex marriages, and several other states have granted unmarried gay and lesbian couples the same legal rights as married heterosexual couples.
The census did not verify whether same-sex couples were legally married, but relied on respondents' voluntary reporting of their gender and their relationship to the people with whom they live.
Before California voters passed Proposition 8 banning gay marriage in November 2008, same-sex couples were allowed to wed in the state on a number of occasions, including in the summer of 2008, when about 18,000 couples were legally married.
Tuesday's data release also included information about same-sex couples with children. It showed lesbian couples in California are far more likely to have children than gay couples.
Some 24 percent of female-headed same-sex couples have children, while just 9 percent of male couples do. Those percentages translate to 6,203 unmarried and 4,806 married lesbian couples with children, and 1,819 unmarried and 2,870 married gay couples.
The data revealed some interesting patterns. The state with the highest percentage of married same-sex couples is Massachusetts, which was also the first state to legalize gay marriage.
But same-sex couples in Vermont were the most likely to be married. That state legalized gay marriage in 2009.
The figures released Tuesday were revised from earlier counts, after the Census Bureau discovered that a data-recording error had resulted in inflated numbers of same-sex couples.
The Census Bureau does not plan to release information about married same-sex couples for cities or counties, partly due to concerns about confidentiality.
Making it possible to identify an individual person or family is “the last thing we want to do,” said Martin O’Connell, the chief of the bureau’s family statistics branch.
The National Gay and Lesbian Task Force, which helped convince the Census Bureau to report information on same-sex married couples, applauded Tuesday’s release in a statement: "The data released today represent another step in erasing the invisibility of our lives. No longer are our marriages rendered invisible in the snapshot of our country provided through the census. And no longer can anyone ignore the presence of our relationships all across the country.”
This chart shows the states with the highest percentages of same-sex couples. Click on column headers to sort: