I've seen a different statistic, shows male preferences worldwide. Westerners are more inclined to Google teen porn, whereas easterners prefer milf/mature.

The reason behind this might be cultural (it's something we've read in anthropology class) since in the west youth is majorly celebrated as attractive. On the other hand, in the east (mainly talking about Muslim cultures) women are covered and as long covered they deserve man's respect. Above that, they fulfill their 'purpose' by birthing children and therein gain the ultimate respect. It doesn't diminish with age.

So, this might be a product of that, and in this chart mature is just beneath teen - I believe because the east simply has worse internet connection