"Doubling time" is the number of years it would take a population to double in size at its current growth rate. The doubling time is found by dividing 69.3 by the growth rate. Calculate the doubling time for the following countries:
a) Afghanistan: growth rate 3.5 percent
b) Belgium: growth rate 0.2 percent
c) Canada: growth rate 1.0 percent
d) Bangladesh: growth rate 1.6 percent