Longevity: Social Aspects

Mortality trends by age may be visually represented through survival curves, which follow a hypothetical birth cohort of one hundred to show what proportion survives to later ages. Figure 2 compares survival curves for selected years. Note that in the bottom curve, survival probabilities are relatively low, particularly at young ages. In 1900, 20 percent of individuals died between birth and age ten; today, less than 1 percent face a similar fate (also see Table 1). Thus, one distinguishing feature between survival rates of 1900 and today is substantial improvement among infants and children.

In 1900, survival chances were also lower across the entire life span. Out of one hundred newborns, only seventy-seven were expected to reach age twenty, fewer than half were expected to attain age sixty, and just thirty-two were expected to reach age seventy. In contrast, based Figure 2 Percent surviving by age: United States, selected years SOURCE: Adapted from: Murphy, S. L. "Deaths: Final Data for 1998." Monthly Vital Statistics Report 48 (2000): 1–108. Also from: Anderson, R. N. "United States Life Tables, 1998." National Vital Statistics Reports 47 (2001): 1–38. on 1998 survival rates, almost 90 percent of newborns can expect to reach age sixty.

Between 1900 and 1930, survival drastically improved for infants and children, and also improved for other ages. Between 1930 and 1960, survival improved substantially for middle-aged individuals. And between 1960 and 1998, mortality improvements were significant at the older ages. In fact, individuals aged eighty-five and older have experienced remarkable declines in mortality over the last several decades. Out of one hundred individuals born, just three could expect to live to age ninety in 1930; by 1960, this number doubled, to six; and between 1960 and 1998, this percentage more than tripled.