Okay, so the US isn't quite the top country (4th in my estimation), but out of 76, I think it's safe to say that the American students made an excellent showing. And look how happy they are!
The results, taken from coach Paul Stanley's reports, are:
China: four gold, one silver (total score 226.7)
Russia: Three gold, one silver, one honorable mention (216.1)
Korea: Two gold, three silver (217.2)
USA: Two gold, three silver (204.2)
Japan: Two gold, two silver, one bronze (206.9)
Iran: Two gold, two silver, one bronze (202.4)
Some say that the performance of a country has a lot to do with its size, and I think it's rather telling that three of the largest nations landed in the top four slots. Anyway, congrats to all the students who competed. And to the all-medaling US team, Physics Buzz salutes you.