Your exponential growth formula, P(t) = A e^(kt), contains two unknown constants, A and k. Once you find them, you can find the population for any t. (I assume, t is measured in years.) From your "story", you have:
72 million = P(1992) = A e^(1992 k)
76 million = P(1998) = A e^(1998 k)
From these two equations, you can find the two unknowns A and k (do it yourself). Once you do, your answer is
P(2012) = A e^(2012 k)
