No doubt contraceptives are a part, but they are actually taken by a small minority of people. They are only applicable to relatively young females, those capable of having children. Younger children and older women aren't much of a market. Depending on what ages you want to pick, the applicable population is probably less than 1/4 the total, with a smaller subset of that actually taking.

A quick googling says that 28% of women of "reproductive age" use the pill, which by my math is about 14% of women overall and 7% of the total population.