[jarek]

I don't think it's quite as simple. Poland has been dubbing foreign TV/movies since the early 90s (in addition to having a rich homegrown tradition of children's entertainment) and English among younger generations is widespread and quite good, if not Scandinavia/Netherlands good.

I'd be willing to bet a correlation with country's population and relative economic power would be much stronger.

[iaskwhy]

It might be then good to analise another country, a poorer one and not in the north, say Portugal. Almost nothing is dubbed in Portugal and you can see quite a difference between Portuguese and Spanish people speaking English. Same for French or Italian people.

Still, Scandinavian youth seem to have almost perfect English and that is not true about Portugal where it's mostly good enough. I'm sure education has a role here somewhere.