Different studies have found very different figures. The link that I provided includes a range of figures from different studies for different kinds of pedophiles ranging from 5.2-150 victims/pedophile. One of the reported numbers for non-incarcerated heterosexual pedophiles was 19.8. It looked like a reasonable figure, so I used it (after rounding).
It should be noted that I started drawing my figures with the assumption that I'd find that the number was hopelessly overinflated. When I got done I could have easily picked other numbers to show that. But I decided to be honest and report the first set of reasonable numbers that I tried.
According to kenjackson's post and data, it's closer to 110 people. This seems to put the real number closer to 0.2% of the population.
That being said, this type of context-less extrapolation can be dangerous.