Estimates of the number of Christians in China vary greatly. In A Star in the East: The Rise of Christianity in China, Stark and Wang chose 1980 as the base year for their estimates. Christianity had just become legal and somewhat visible.
They estimated that in 1980 there were 10 million Christians in China.
Next they examined a 2001 study by the Research Centre for Contemporary China (Peking University) and a second survey conducted in 2007 by Horizon, China’s largest most respected polling firm.
They concluded that in 2007 there were 60 million Christians in China.
If their estimates are correct, from 1980 to 2007 Christianity in China grew from 10 million to 60 million at a rate of 7% per year.
If that rate of growth continues for just the next ten years, there will be more Christians in China than any other nation on earth. If a 7% annual growth rate continues, by 2040 there will be almost 600 million Christians in China.