Go to China and have a survey, to find out who are included in that counting.
A Christian Brother from China came back to US from a recent visit excitedly told us that his village and adjacent areas were full of Christians, but only found later that he was cheated by his countryman.
Some people from abroad WISH miracle happen in China, and the number of Chinese Christians is close to the number of Communist members. To put it exactly, those two numbers are probably the same; hope you understand what I mean here: Christians are considered enemies in *ists' eyes, and the latter simply told the outsiders they are real 'Christians'.
If you still believe that number, ask the most famous Chinese female Christian, Xiao Min, who has heard and recorded thousands of hymns. Unless you WISH that number is true, without solid support, based on other people's number.
May God bless you to see the truth. :)