Earlier you correctly warned that your sample set likely is not representative of Threads users as a whole, though. So, extrapolation to the general is likely not valid.
As a counter example, @jwz found:
> Of the 655 accounts I used to follow on Instagram, […] exactly ZERO can be followed from Mastodon dot social. If there's something they have to turn on to make it happen, zero of them have done so.
https://www.jwz.org/blog/2024/08/rumors-of-threads-dot-net-federation-have-been-greatly-exaggerated/
So, extrapolate from that, and it's *zero*.