Mark Thoma at Economist’s View posted the following graphical representation of changes in the age distribution of the population of the U.S. between 1950 and today, and projected to 2050:
The bump, slowly moving off to the right, is the baby boom generation. The downward slope in the lines as you move to the right represents a population with a larger percentage of older people or, in other words, an older average age. If the forecast is correct, about 10 percent of the U.S. population will be over 75 by 2050.
Mark observes that many examinations of historical trends likely need to take into account this changing age distribution. For example, he asks:
…with a larger and larger fraction of the population moving into the asset liquidation phase of their life-cycle, how is the saving rate affected? How much of the change in the saving rate in recent years is attributable solely to changes in the age-distribution of the population?