bragi,
You have it in a nutshell there...your 30% number is year round, in the warmer months that number can easily double!
They also have an outstanding mass transit system. I read
Copenhagenize on a regular basis and am constantly amazed. We also have to remember the history behind the movement. After WW2 fuel was in pretty short supply in most of Europe, but not in the US. The Danes also made the political decision to support alternative transportation. It wasn't with out it's critics, even today. What I find interesting is all the complaints we here from businesses and people about the bike lanes were heard over there, but they have proven them wrong.
And yet another thing to keep in mind, the standard of living in Denmark is one of the highest in the world.
Aaron