So you gotta define what we are talking about when we ask how many card counters or female card counters there are.
I'll break my guess and that's all it is, down this way. Recreational, hobbyist's weekend warrior type probably with a job, I have no idea, probably a lot....like hundreds or a thousand across the country. How much of a winning game they are playing varies. With all the locations probably a good number that go out to their local casino less than an hour from home, a couple times a month and probably a significant number are female.
You get into the supplemental group, often retired supplementing retirement income, sometimes supplementing a job or career or they consider AP a second career and would guess maybe 100, maybe 150 with all the locations available now and 90% male.
The serious or professional type players, I am going to guess under 50 and if you are talking exclusively blackjack card counter, I may be it.
Ok, maybe 10-12. And almost all these are male. That is why I have said a number of times, I think a female has a built in advantage.