3b hair is common amongst the mediterranean race which embarks the mediterranean basin countries. In Spain, this type of hair is relatively less rare than in other european countries (I have been to quite a few and can confirm this) which is one of the reasons why spanish women (from Spain) are amongst the most beautiful women in the world.
As much as I detest hair profiling, this sort of hair is also of a similar frequency to Spain in countries such as Morocco and Turkey, and these are countries whose population is relatively homogeneous. Of course, countries like Cuba or Colombia have a high incidence of "type 3b" haired people due to the mixed ancestry but this type of hair is not only for those of mixed race.
In fact, the mediterranean beauty prototype is that of dark curly hair, big dark sensual eyes and olive-coloured skin.