that's not a good reason at all as to why more Swedish people know about jailbreaking
I think it is. If you have a mobile network you've paid for and allows 7.2 Mbit/s or more with no or few restrictions, you seek solutions to the problem that Apple/AT&T will not allow full use of the network. When solutions are found, they are spread to other users through friends and internet forums. If you live in the US and don't even have 3G cellular or are not allowed to use it according to your plan, there´s no problem to seek solutions to.
AT&T is starting to deploy 3G in selected states at the end of 2009, we've had fully working 3G cellular networks for several years. If Apple haven't changed their policy in a couple of years, US citizens will start jailbreaking en masse when 3G is available but cannot be used.