The natural increase rate, the crude birth rate, and the total fertility rate tend to run concurrently. To find the natural increase rate, subtract the crude death rate from the crude birth rate and divide by 10. Crude rates are found by the number of live births per 1000 people as of the middle of each calendar year. To find the total fertility rate, this calculates the average number of live births per 1000 women who would go through the "childbearing years" while having the expected number of children for a person of their age, ethnicity, and socioeconomic status in that region or country.
