Of course it's true. Even the Guinness Book knows about it, though there's some disagreement about the precise figures.

The following is also true. Many years ago I was discussing the matter with a (shall we say, "left-wing"?) college classmate.   

She was unperturbed, pointing out that "China has such a huge population that it wasn't that big a percentage."

She added that "revolutions are fragile" and "have to assert their authority until they can stabilize."

She seemed to be quite a normal person until that moment.