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. Some writers suggest that there is a fifth stage where birth rates fall below death rates so population levels fall.