Yes, that's available. But that doesn't tell us which player has been the most prolific tank to air (maingun) shooter, which has been the original question. The kill numbers encompass also pintle and proxy kills, the latter one being the vast majority of aircraft "kills" by tanks.
I have, for example, almost 900 recorded plane 'kills' in tanks and tank destroyers, but certainly not more than two, maybe three dozen of these were actually hit by my main gun.
Yes, I can see the difficulty of separating out pintle and proxy. However, certainly the most prolific ground-to-air data is available. Perhaps as a wish list item we could request HT to separate the "platform" into its different gun positions? That might make for some interesting bomber stats as well.
DALE: Make it SO... kidding, of course. Still, I'd sort of like to see that. In fact, I'd like to see, for example, 999's numbers on the different B-17 gun positions. That way, it'd be possible to make some hypostheses about which avenue of approach is best, in his case, and perhaps across the board with this most salamanderly of bombers. That way, when I'm falling out of the sky, oiled and sans a wing, I can know that I've stumbled across a relatively new way to get shot down by a B-17.