RJ was pretty clear it was all channelers in the bell curve.

For Papazen, while I have spoken of souls being born with the ability to channel in response to questions, I think of it as being genetic also. In the Age of Legends, between 2 and 3% of people had some ability, following a bell curve distribution in strength. For over 3000 years, though, Aes Sedai have been removing men who actually learned to channel from the gene pool. They have been very efficient at this. As a result, the "present day" sees about 1% of the population who can learn to channel, with a much, much smaller percentage of that being born with the spark.

This is the entire channeling population (2-3% in the AoL, 1% in this Age).

Regarding the percentage of women who could test for the shawl, it would be 62.5% of the bell curve. I’ll leave the maths to you for an idle moment. The question doesn’t really apply to men, since the Black Tower accepts anyone who can learn to channel, but if the White Tower limits were applied, it would be roughly 65.4% of the bell curve. Although, considering the effectiveness question, they should probably set it at the same 62.5%. Again, the maths are all yours. Regarding the levels of male strength, while the weakest man and the weakest woman would be roughly equivalent, you might say that there are several levels of male strength on top of the female levels. Remember to integrate this with what I’ve said elsewhere about effectiveness, though.

In this quote, he even mentions the strongest men and women, and levels of strength between them.

Frustrating as it may be, I really don't think we can twist the bell curve to be anything but what it is.