further compression or change in symmetry. Projections for survival and the distribution of deaths by age from 2000 to 2100 produced by the Social Security Administration’s Office of the Chief Actuary for the Social Security and Medicare Trustees show a continued shift to the right with relatively little further compression or change in symmetry.
Chart 12 - U.S. Population Survival Curves to 2100 - Female
for Selected Calendar Years (based on Period Tables)
P robability of S urvival from Birth to Given Age
Chart 13 provides an additional graphic illustration of the progression of survival in the United States historically and as projected. Shown here are the ages for survival rates of 50 percent, 10 percent and 0.001 percent (1 in 100,000 births). The last of these represents a reasonable definition of a “practical omega” for the purpose of analysis. Because it is difficult to state the age to which survival is possible, and where survival to one year beyond that age is impossible, a true theoretical omega is a philosophical debating point. A practical omega as defined here seems to obviate the need for this debate and allows a meaningful discussion of survival.