The U.S. contains 3,141 counties or county equivalents. Conclusions Natural decrease is a function of a complex interaction between fertility, mortality and migration over a protracted period. Where natural decrease is a product of prolonged outmigration of the young, it reflects a loss of human capital due to the lack of proximate opportunities. With continuing outmigration and historically low birth rates, the future for many of these areas is a significant concern. Though the likelihood of future natural decrease appears high for some areas, recent demographic trends suggest that it may not be a foregone conclusion.
Preliminary evidence suggests that some age structure shifts are occurring.
The growth rate of the older population in rural areas is now below that of the younger population for the first time in recent history. If these trends are sustained for an extended period, the incidence of natural decrease in rural America may well diminish. It is also possible that counties with a long history of natural decrease will eventually reach a new demographic equilibrium where births and deaths again in balance. However, little is known about this phenomenon and more research is needed to ascertain whether and when such a new equilibrium may be achieved. With falling nonmetropolitan age-specific fertility rates and an age structure much less supportive of fertility, natural decrease is likely to continue to be a concern in the future.