Also, just looked up the Taiping rebellion. While they were misguided and wrong most often, they were a marked improvement over the Qing dynasty. They had some weird policies, but they abolished slavery, abolished foot binding, and declared the sexes equal. And they abolished private ownership, and created a classless society. Sounds like a weird blend of communism and christianity. 

Found the 20 million, which wiki said was the best estimate. Best estimate for Mao was circa 74 million.