My family is Scottish and a little Irish, and no one has red hair... weird I know. But yeah, I would consider more Irish, Scottish and English people to have red hair than anywhere else, defenatly not China or Japan... *sniggers*
Actually a significant percentage of the population in both China and Japan have red hair, its just not that bright bright red that the stereotype of a scottsmen always has while hes playing his bagpipes out on his hill with all the sheep.