NEW YORK (CNNMoney.com) -- The financial balance of power in American marriages is shifting.
A Pew Research Center survey released Tuesday found that 22% of men made less money than their wives in 2007.
By comparison, 4% of husbands earned less than their wives in 1970.
A shift in education patterns was a factor in the Pew report, which polled U.S.-born 30- to 44-year olds.
In 1970, 28% of husbands had more education than their wives. By 2007, that figure dropped to 19%.
Slightly more than half of spouses had the same education level in both 1970 and 2007, the most recent year for which data were available.
"For a long time, men didn't need education to make a decent wage -- they could go into manufacturing or other labor," said Jenny Wittner, associate director of the advocacy group Women Employed.
"Women had to get an education to keep up, and over the years that has started to translate into a difference in wages," Wittner added.
The report cited several societal and economic reasons for the jump. Marriage rates have declined across the board since 1970, and rates have gone down most sharply for the least educated.
The most educated are far more likely than those with less education to be married, and that gap that has widened since 1970. And since more education is linked to higher earnings, marriage especially boosts a household's spending power.
Pew's report was compiled from data collected before the recession hit, and said that the downturn will only exacerbate those trends as men have especially felt the job crunch.
The report cited government data that said males accounted for about 75% of the 2008 decline in employment among "prime-working-age individuals." As a result, the percentage of women in the workforce continues to inch toward equilibrium, as women now comprise 47.4% of the total.
But Wittner noted "it may not stay a so-called 'men's recession' forever, and that shift will hurt households as the woman's income becomes more important."
Unmarried adults and the marriage advantage: For singles at all levels of education, men's incomes fared worse. In 2007, unmarried women had higher income than their 1970 counterparts. But single men without any college education saw their inflation-adjusted earnings decrease, and they did not have a wife's wages cushion the decline.
Similarly, single men who did not complete high school or who had only a high school diploma had lower household incomes in 2007 than their 1970 counterparts -- those with some college education saw income remain the same.
One exception to the marriage advantage: Married women without a high school diploma saw their inflation-adjusted household incomes fall 2% from 1970 to 2007, while those of their single counterparts grew 9%.
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