whites, 29.8 years for blacks, and 26.5 years for Hispanics (U.S. Bureau of the Census, 1996b).
One major trend underlying the aging of the population has been the decline in the total fertility rate. A white woman in 1900 could expect an average of 3.56 children by the end of her childbearing years. Nonwhite fertility rates at the turn of the century were higher but, again, the estimates are subject to greater error. In contrast, by the mid-1990s, a white woman could expect to bear just under two children, whereas black and Hispanic total fertility rates were somewhat higher (Bachu, 1995). By the late 20th century, families were smaller, and there were many more families and households with a single parent. More families and households now are likely to have both spouses working, or the only adult in the family or household working.
Between 1890 and the mid-1900s, the participation rate of women in the labor force increased from 1 in 5 to 3 in 5 (Monthly Labor Review , 1997:61; Sweet, 1973). Currently, during the prime working years from ages 25 to 54, about three-quarters of women are working. Figure 2.1 describes the sex composition of the workforce by age in the period 1948–1996. Continuing the longer-term trends, the panel for 25- to 54-year-olds shows the convergence of the representation of men and women in these age ranges in the workforce. Although less pronounced, this same convergence appears for the other three age groups shown in the figure (16 to 24, 55 to 64, and over 65). Thus, at young, old, and prime working ages, women's share of the workforce has increased.
At the turn of the century, African Americans were less than 15 percent of the population, and Hispanics and Asians were less than 5 percent (Passel and Edmonston, 1992; U.S. Bureau of the Census, 1992). Furthermore, the major source of immigrants was from Europe—over two-thirds of whom were male. As we approach the end of the century, the origins of immigrants have diversified, with much larger shares from Asia in particular, and