It's a very - though not entirely - similar distribution to that of blonde hair. The concentration of these really sort of strange traits around the Baltic makes you realize that northern Europeans, and especially Swedes and Finns, are kind of a race of mutants. Not that there's anything wrong with that. But it makes you wonder why these adaptations never showed up on a large scale in northern Asia and northern North America. Those areas were certainly populated long enough for such traits to take root.
