Not going to lie, you guys have done remarkably well here. Mad about You, Friends and Full House are, without a doubt, the whitest shows in existence. Mad about You and Friends take place in NYC and there are never any minorities, like, at all. Frasier took place in Seattle in the 90s...pretty heavily white populated, so there was an excuse there. Seinfeld featured a minority as one of the four and always had black and Latino guest stars. Friends had like, none and they lived in NYC. Mad about You, same shit, though most of that show revolved around two people in their own house.
I think Full House edges out Friends though. 87 regular cast members and none of them with even a tan.