The younger a population is, the higher its growth rate will be.
Work Step by Step
Conversely, an older population will have a slower growth rate that may even become a declining growth rate depending on the distribution of ages involved. The more individuals in a population that are of reproductive age, the more they can (and typically will) reproduce. As humans age, their ability to reproduce declines, so the larger the proportion of older humans in a population there is, the more their lack of reproductive activity will affect the growth rate.