And, actually I would have gotten 5/5, but #4 and #5 would have been guesses.
There's also the issue of the groups interviewed. E.g. I'd expect foreign students in the US to do better than the average US HS student; similarly I'd expect US HS students visiting England to do better than the average English HS student on English history. (I may be wrong about that though.) Why? The foreign students likely have more interest in the country they're visiting than someone who grows up there, so they would take the time to learn more about it.
Cheers,
Scott.