E C O N O M I C R E P O R T O F T H E P R E S I D E N T

gle mothers the median rose from $11,300 to $15,000. The median earningsof all wives with children rose from zero (more than half had no earnings) to$10,400 during this same time period, and from $7,600 to $18,000 forworking mothers. As a result, married working mothers’ earnings today represent30 percent of the couple’s combined earnings, compared with only 15percent in 1968. In addition to raising average family income, mothers’ earningshave dramatically increased the proportion of families who are well off.The share of working wives earning more than $20,000 rose from 14 percentto 43 percent between 1968 and 1998, and the share of single workingmothers earning above $20,000 rose a smaller (although still sizable)amount, from 21 percent to 37 percent. Among married couples, wives’earnings have had a big effect in increasing the proportion of wealthy families:in 1998 only 18 percent of all men earned more than $60,000, butwhen wives’ earnings are included, 37 percent of all married couples withchildren had combined earnings above $60,000. In contrast, among familiesheaded by single women, only 2 percent had earnings above $60,000.Thus, although most women now contribute to family income, there arepronounced differences across different types of families. These differences inmothers’ contributions can be traced to differences both in wages and inhours of work.As discussed in Chapter 4, women’s wages have risen over time, in partbecause of rising skill levels. But single mothers have experienced slower wage178 | Economic Report of the President