Beyoncé was right: It was all the single ladies who put their hands up. New research reveals Barack Obama owes his re-election victory to the unmarried women who turned out in their millions to vote for him.

Nearly a quarter of the voters in Tuesday's election were unmarried women – and Obama captured more than two-thirds of their votes, 67%, according to research released on Thursday by the Women's Voices Women Vote Action Fund.

"Unmarried women were the drivers of the president's victory," said Page Gardner, the president of WVWVAF.

The finding might seem unsurprising after a campaign season punctuated by offensive and biologically illiterate statements from Republican candidates about rape and pregnancy. But pollsters said the newly identified electoral bloc of unmarried women voted for Obama for bringing the country through the recession – with the Democrats' support for healthcare, equal pay, and Planned Parenthood came a close second.

And marital status was crucial. "It's all about the marriage gap," said Celinda Lake, a Democratic strategist and pollster.

Mitt Romney actually did better than Obama among married women, outperforming the president by seven points. But Obama obliterated Romney when it came to the battle for the votes of unmarried women, beating him by 36 points.

American pollsters have a history of coming up with new labels for core sections of the electorate. In Bill Clinton's time, there were the soccer moms. George Bush had his security moms in the 2004 elections. In the 2008 contest, Sarah Palin tried to create a new brand of conservative woman with hockey moms and mama grizzlies.

But in striking demographic shift the most crucial component of the women's vote is no longer white, married middle class suburbanites but a broad coalition of unmarried women, people of colour and those under the age of 30.

The unmarried women of the 2012 make up almost 40% of the African American population, nearly 30% of the Latino population, and about a third of all young voters, or 32.7%, according to the research released on Thursday. They are divorced, separated, widowed, or have never married.

"They had an enormous influence on Tuesday's election," Gardner said.

Single women have traditionally been Democratic voters, largely for economic reasons. They tend to have less money than married women – because they don't have a husband's earnings to fall back on. They also tend to be less educated.

"A lot of it simply has to do with economics and affluence," said Susan Carroll of the Center for American Women and Politics at Rutgers University.

"The Democrats are much more supportive of the social safety net, the programmes that help people who need financial assistance, whether it be unemployment insurance, child nutrition programmes, Medicaid, the whole infrastructure of the social welfare state that helps people who financially are more in need."

The clue to Obama's re-election victory however could be a combination of changing demographic patterns and turnout.

More and more Americans are single. Singe people are now the majority in about 15 or 16 states – several of them the swing states that decide presidential elections, said Celinda Lake, the Democratic

pollster and strategist.

Among women, unmarried women made up about 20% of the electorate in the 2008 elections. By 2012, about 23% of voters were single women – and they opted overwhelmingly for Obama, giving him 67% of their votes.

The challenge for Democrats, however, is that unmarried women have not always been reliable voters. Nearly 11 million of the single women who turned out for Obama in 2008 skipped the 2010 congressional elections, which led to the Republican takeover of the House of Representatives.

"They have been for a while a reliably Democratic constituency. What they don't always do is turn out to vote. But there was a huge effort on the ground," she said.

Unmarried women had an additional incentive this year, when Republicans seemed to be adopting extreme and retrograde positions on equal pay, birth control and abortion – which the Democrats quickly jumped on and labelled a "war on women".

Then there was Romney's now-notorious 47% remark. "On economic issues they really believed a guy like Romney couldn't possibly understand their lives. They are clearly in the 47% so they thought here is someone who doesn't want to represent me," Lake said.

Along with crediting Obama for guiding the country through the recession, unmarried women strongly supported his equal pay provisions – which was the first piece of legislation the president signed into law. They backed Obama on health care, including birth control and abortion, which Lake argues are as much economic as social issues.

Another critical factor may have been pride. "A lot of it has to do with the different nature of their lives. They are very economically stressed and stretched in terms of the wage gap. There is a greater wage gap with unmarried women than with married," said Gardner. "There is a sense that they are on their own. They know and they are very proud of the fact that they are making it on their own. They are contributing to this country in enormous ways but they are on their own so it is a different world view."

Or, to borrow from another Beyoncé hit, they are the Independent Women voters.