"25% of 600,000 is 150,000. So even if every Muslim in Norway was an immigrant and they all lived Oslo, you would be off by more than a third."

Even at that the you are being a bit gentle on his figures. The CIA figures actually give the population of the country as only 4.691 million and Oslo at 875,000 (not the 600,000 originally quoted here) so at 1.8% of the country's population that gives a maximum 84,6000 Moslems and if they all lived in Oslo it would make it only 9.66% Moslem. If the figures quoted by the CIA site are correct of course.

The BBC seemed to initially be making a big thing about Islam being the second biggest religion in the country. It was stated more than several times. I imagine if we treat all the different forms of Christianity as one religion then Islam will be the second religion in virtually every European country. Something so normal doesn't seem to be so newsworthy!