Overwhelming, the world over, people from less developed countries try to migrate to more developed countries. If Norway had lots of highly skilled, well educated engineers, doctors and nurses moving from Pakistan, India, and Bangladesh would it make you feel different? Also it is weird that you used the term "legal". Due to natural geography, it is very hard to illegally migrate to Norway. Probably, legit visa overstay is the most common. Also, during the Arab Spring and Syria Civil War, many refugees came by bicycle (no joke!) from Russia to far northern Norway.