Growth rate (r) in ecology is given by the substraction of the death rate from the birth rate. Therefore, the annual growth rates (per 1,000 people) for the years 1990 and 2010 are,
1999: r = 31 - 9 = 22
2010: r = 25 - 5 = 20
If you want to calculate r per habitant, which is the form most used in ecology modelling, you should divide the previous answers by 1,000:
1999: r = 0.022
2010: r = 0.02
