Are you taking that number out of your arsenal or from a source? AFAIK most South Korean pilots are actually doing their training in the US, since it's much easier to accumulate the hours, and there's more GA. I would think their training is about the same as US pilots.

Although the US airways system is much more developed and used than Korea's, given that Korea is a smaller country and has an extensive bullet-train network. So I could buy an argument where US pilots just fly more.