According to Pew:

— “Breadwinner moms are made up of two very different groups: 5.1 million (37 percent) are married mothers who have a higher income than their husbands, and 8.6 million (63 percent) are single mothers.”

— “The growth of both groups of mothers is tied to women’s increasing presence in the workplace. Women make up almost of half (47 percent) of the U.S. labor force today, and the employment rate of married mothers with children has increased from 37 percent in 1968 to 65 percent in 2011.”

The research center also released results of a related survey of public opinion. Among the highlights:

— “About three-quarters of adults (74 percent) say the increasing number of women working for pay has made it harder for parents to raise children, and half say that it has made marriages harder to succeed. At the same time, two-thirds say it has made it easier for families to live comfortably.”