An account, but not a complete explanation, of changing rates of fertility, mortality, and natural increase . These changes are held to occur as a nation progresses from a rural, agrarian, and illiterate state to a predominantly urban, industrial, literate one. The High Stationary Stage . Birth and death rates are high and the death rate fluctuates from year to year. The Early Expanding Stage .
Fertility remains high, but improved conditions mean falling death rates.
Population therefore increases. The Late Expanding Stage . Death rates are low and fertility is declining but population is still increasing. The Low Stationary Stage . Birth and death rates are low and the birth rate fluctuates.