The Pew Research Center findings released Wednesday show a dramatic change from five decades ago, when just 11 percent of women with children were the primary source of support for their family.
The data reveal single mothers make up nearly two-thirds of these women, while married mothers who make more money than their husbands make up about a third of the breadwinning moms.
Researchers say long-term changes in demographics have contributed to the change. Women currently hold more bachelor degrees than men and make up nearly half of the workforce in the U.S.
Some information for this report was provided by AP and Reuters.