Hi there!
It didn't, I live in England (hence nick-uk).
Sorry I can't help. Although I'm led to believe (mostly from ER) that the american exams are intensely hard. Although was encouraged to see them using Robbin's pathological basis of disease on ER a while ago (so the US courses can't be that different to ours).
Anyway, I reckon I'm currently at the lower end of what PR can achieve, but still the other day, when i was regular reading, i noticed how quickly i was burning through the text (Edelman's Bright air, brilliant fire; a top notch read).
Once again sorry I can't say anything more about USMLE, but i am chuffed by the number of med students frequenting this forum.
Nick