The number of same-sex households in Hawaii jumped a whopping 78 percent between the 2000 and 2010 census counts, which researchers say reflects a growing willingness of gays and lesbians to identify themselves as couples in the islands.

Hawaii’s 78 percent increase ranked fifth highest in the nation last week after census data on gay and lesbian households was released for 41 states, said Gary Gates, a demographer at UCLA School of Law’s Williams Institute who has been poring over the data.

The 41 states combined for a 50 percent average increase in same-sex households between the 2000 and 2010 census counts, Gates said.

Some of the states with even bigger gains than Hawaii — such as Montana (88 percent) and West Virginia (80 percent) — likely had far fewer couples willing to identify themselves as same-sex in 2000, Gates said.

"Montana and West Virginia, in particular, were really conservative 10 years ago and had a bigger pool of hidden same-sex couples," Gates said. "Hawaii doesn’t fit that pattern. Hawaii’s been on the map for lesbian and gay couples for years."

While he could not pinpoint a specific reason for Hawaii’s 78 percent gain, Gates said, "I have faith in those Hawaii numbers."

The 2010 Census showed 4,248 same-sex households throughout the islands, with the largest number — 2,530 households — on Oahu. Urban Honolulu’s 1,186 same-sex households represented the biggest block of any Hawaii community.

Hawaii island had 839 same-sex households in 2010, followed by Maui County with 614. Kauai County had 263 same-sex households, followed by two households in tiny Kalaupapa on Molokai.

There were children being raised in some 905 same-sex households in Hawaii — or 21 percent. Fifty-six percent of those households were female.

The increase in Hawaii’s same-sex households follows three decades of changing attitudes in the islands toward gay and lesbian rights.

Hawaii was considered the first state likely to sanction same-sex marriage after the Hawaii Supreme Court in 1993 ruled that denying same-sex partners the right to marry violated the state Constitution.

Then in 1998, an overwhelming 70 percent of Hawaii voters approved a constitutional amendment to grant the Legislature the authority to reserve marriage for a man and a woman.

Gay rights advocates lobbied lawmakers for years in a battle to allow either same-sex marriage or civil unions in Hawaii, culminating in February when Gov. Neil Abercrombie signed into law a bill making Hawaii the seventh state to legalize civil unions. Under the new law, which goes into effect Jan. 1, same-sex and heterosexual couples can enter into civil unions and receive the same rights, benefits and responsibilities as married couples.

"We were a pioneer in this field with the Supreme Court’s ruling," said political analyst Dan Boylan, a retired University of Hawaii-West Oahu history professor. "Since then, there’s been a generational change that’s happened across the country with significantly greater tolerance for gay and lesbian couples. Are we as friendly toward gay and lesbian couples as New York, which now allows same-sex marriage? No. But the perception is that we are definitely friendly to same-sex couples."

Shanna Clinton, a doctoral student at the University of Hawaii, and her partner, Heather Youngs, moved to Oahu four years ago from Seattle and were not counted in Hawaii’s 2000 census.

But they proudly identified themselves as a Hawaii same-sex household in 2010.

"We are definitely part of the increase," Clinton said.

Unlike Seattle, Oahu does not have clearly identifiable gay or lesbian neighborhoods and it took a while before Clinton and Youngs felt a part of Oahu’s gay community, Clinton said.

"In Seattle, you have gay neighborhoods and bars and clubs and a lot of community groups, resources and social services for the gay, lesbian, bisexual, transgender community," Clinton said. "For gay men in Hawaii, there’s a little bit more visibility around Waikiki, but Waikiki’s certainly not a gay neighborhood."

Clinton finally felt she had become part of a growing gay and lesbian political movement in Hawaii when she testified in favor of civil unions at the Legislature.

"While I’ve been aware of more political activism," Clinton said, "there still isn’t a lot of public awareness of the gay and lesbian community here and their issues."

Jeff Merz, an urban planner and member of the Waikiki neighborhood board, also wasn’t counted in Hawaii’s 2000 census because he hadn’t moved here yet.

But Merz and his partner, Ka‘iwa Metzker, identified themselves as a Hawaii same-sex household in 2010.

"Gay people are much more comfortable in general and aren’t as afraid to acknowledge who they are," Merz said. "Society’s attitudes also have changed rapidly. I see significant changes which, of course, is very heartening for me."

The census data does not break down differences between gay and lesbian couples, such as incomes and neighborhoods.

But Merz and others believe Hawaii follows national trends in higher incomes for gay couples compared with lesbian couples. Gay couples also tend to prefer urban areas over suburban and rural communities generally preferred by lesbians, Merz and others said.

"Gay men tend to congregate in more urban areas and inner cities, whether it’s the Castro or South Beach," Merz said. "Lesbians do tend to earn less and tend to prefer more suburban areas and even rural areas. My male friends tend to live near Waikiki. My lesbian friends gravitate toward Mililani, Kapolei and even Waialua. They’re definitely more suburban."

Clinton and Youngs moved from Manoa last year to a bigger house in St. Louis Heights. And three weeks ago, they became the proud parents of twin daughters.

"Hopefully," Clinton said, "we won’t get too much more suburban than this."

The growing number of same-sex, Hawaii households is unlikely to have any effect on the political redistricting currently under way because Hawaii’s reapportionment project only reviews population counts and basic breakdowns of major ethnicities, said project manager David Rosenbrock.

But gay and lesbian households that mobilize as a voting bloc, in general, would likely support or oppose their individual legislators depending on how their lawmakers voted for Hawaii’s civil unions law, Boylan said.