Whatever happened to knee-length skirts?

I've been window shopping on line for a while, and whenever I look for skirts it's almost impossible to find any that meet the knee. When I look for miniskirts, the majority come to just under the ass and when I look at midiskirts, the majority are mid-calf length. It'ss like the only short and mid-length skirts that are still manufactured are either "practically a belt" length or "almost a maxiskirt" length.

(images from YesStyle)

Where are all the knee-length skirts?!