The U.S. population at the end of the century was not conspicuously mobile. Residential mobility the movement of individuals and families from one dwelling to another, whether across the street or across the country declined during the century. As the upper chart shows, the proportion of people changing addresses from one year to the next declined from one of five in 1948, the earliest year for which national data are available, to one of six in 1999. Studies of residential mobility in several localities strongly suggest that the proportion of annual movers began to decline before 1900. The principal factor affecting the rate of residential mobility is home ownership.
Owners are much less inclined to change dwellings than are renters.
Thus, as home ownership increased, residential mobility declined. A related factor is the rising average age of the population. Young adults move the most, but their share of the population was declining as the average age of the population increased. In 1997, two of every three movers remained in the same county. Five of six movers found new homes in the same state.