The U.S. Census Bureau on Tuesday released new statistics on gay and lesbian couples, prompting renewed calls for more states to legalize gay marriage.

The agency said there were 131,729 gay married households and 514,735 gay unmarried partner households in the United States. Massachusetts, the first state to legalize gay marriage in 2005, had the highest rate of married couples in gay households (43%), and Maine had the lowest (10.3%).

The revised figures are about 25% lower than the bureau's initial estimates released earlier this month. Flaws and inconsistencies in the surveys were to blame for the discrepancy, the agency said.

However, officials stood by their assessment that gay households are growing.

“There's no dispute that the same-sex couples population increased between 2000 and 2010,” Martin O'Connell, chief of the bureau's fertility and family statistics branch. “We're trying to get a better grip on the actual numbers and the actual increase.”

Marriage equality proponents used the figures to advocate for greater access to the protections of marriage for gay couples.

“The Census Bureau's most recent estimates of same-sex couples reiterate the need to end marriage discrimination once and for all,” said Evan Wolfson, president of Freedom to Marry. “The number of gay and lesbian couples in committed, loving relationships, raising families together, continues to grow, leaving more and more families without the critical safety-net of marriage.”

“These findings also confirm that those who most need the support marriage offers – particularly in these tough economic times – live in the places with the fewest protections. The South is home to more gay parents than any other region in the nation. And yet, these families are not only discriminated against by their home states, which exclude them from marriage and bar even lesser protections such as civil union and domestic partnership, but are also targeted for an additional layer of discrimination from the federal government under the so-called Defense of Marriage Act,” he added.

Currently, only six states and the District of Columbia have legalized gay marriage. Roughly 18,000 gay couples married in 2008 in California before voters approved Proposition 8, which rolled back a state Supreme Court ruling legalizing such nuptials.