How much of Zion's population was Red Pills?

The majority of characters in The Matrix films were born in the Matrix and freed later, no doubt because this allows them to enter the Matrix, and thus, you know, be in most of the film. But there are a few characters who are, as Tank puts it, "pure, old-fashioned, home-grown human."

We know from the Architect that Zion is re-founded in each cycle by "13 individuals: 6 female, 7 male", plus the One, all of whom are from the Matrix. But by the time that the next "One" emerges, Zion has swelled to a population of 250,000 or so (if I recall), many of which are the descendants of Red Pills, but are not themselves from the Matrix. For example, Tank.

Are there any stats about how the population of Zion breaks out, between these two categories? Is the majority of Zion's population still being rescued from the Matrix, or has the natural birthrate of the city overtaken the "unplugging" process? Are Red Pills common within the city, or are they disproportionately concentrated in the fleet because they are the only ones who can jack in?