The annual percentage growth rate of a population is the percent change in a population from all factors (births, deaths, immigration, and emigration). A simple method used to estimate the time it takes for a population to double in number is this expression: Population doubling time = 70 / (annual percentage growth rate). The annual percentage growth rate for the Dominican Republic fell from 3.4% in 1961 to 1.2% in 2015. How did the population doubling time change from 1961 to 2015?
a. It did not change.
b. It nearly tripled.
c. It was reduced by more than half.
d. It nearly doubled.