I'm actually quite surprised at that - I was in California last Easter, and was invited out for a meal with some friends.
I sat near their kids, and they kind of interrorgated me about the world in general. They were very good at naming capitals (although they put similar empthasis on States as countries - they thought the capital of a state was equivalent to Paris, or Berlin) and pointing out places on a map. They knew what was happening in the world in general, and surprisingly knew quite a lot of random facts.
However, they didn't know who Hitler was - nor did they believe that they lost the Vietnam war. For 14/15 year olds, i thought that was quite dodgy!