#### Answer

Iraq, $ 1.9\%$

#### Work Step by Step

The mathematical model for exponential growth or decay is given by
$ f(t)= A_{0}e^{kt}$ or $ A= A_{0}e^{kt}$.
If $ k \gt 0$, the function models the amount of a growing entity.
$ A_{0}$ is the original amount, or size, of the growing entity at time t = 0,
$ A $ is the amount at time $ t $, and
$ k $ is a constant representing the growth rate.
If k $ \lt $ 0, the function models the amount of a decaying entity
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The greatest constant of growth rate, k is $0.019$
(that of Iraq).
k is represented in decimal form and represents a $ 1.9\%$ increase of the population per year.