I've not kept statistics, especially that when people purchase they get access to all the OS versions. I'm guessing it's over 50% Windows but Mac is no less than 20% of the purchases. I don't sell my app through the Apple App store - it's just whoever stumbles across my website (I've shared it on Reddit a bunch of times over the years, but not aggressively). I think I mostly got lucky with naming - where "video hub" is close to "porn hub" and people find it unintentionally :)