)For fun, my estimates (completely random cause you dont know who takes what quiz for what reason, some avoid quizzes they dont know (all) the answer for, and the others seek them out) I think on here maybe 25% know ALL the countries (so not all -10 lesser known) and 7.5% know ALL the capitals, even the unpronouncable ones, again knowing 99.9% isnt counted. And the "outside" it is 7.5% for all the countries. and 0.5% for alles the capitals>
These might seem low estimates (looking at all the highscores of geography quizzes) But if the parameter was know 90% correct it would paint a completely different picture, if you could miss a couple.
"outside" would be 20% knowing most countries and 1% most capitals)