It would be right with regards to the skewing, i think. And if that's happening in Norway, it's worse in Sweden and Denmark who has liberal immigration policies. Norway has one of the most unfriendly immigration policies in Scandinavia - your 10 percent is wrong, and the total number of muslims in the country is 35.000, out of a population of 4.5 million. How much is that in %?
Anyway, that small number is probably behind a disproportionate amount of these crimes.