Some experts, like Purdue University sociology professor Fenggang Yang, have no doubt, though, that China is on track to overtake the U.S. as the most Christian country in the world.
"By my calculations China is destined to become the largest Christian country in the world very soon," Yang told The Telegraph. "It is going to be less than a generation. Not many people are prepared for this dramatic change."
The People's Republic of China, which is officially an atheist country, has a population of nearly 1.4 billion. As of 2010, just 5% of China's population, or roughly 67 million people were Chrisitian, according to Pew Research, making it the seventh largest Christian country.
Professor Yang, who wrote 'Religion in China: Survival and Revival under Communist Rule', believes the number of Christians in China will rise to 160 million by 2025 and 247 million by 2030, just as America's Christian population appears to be waning.
This growth may not go unchallenged by the Chinese government, however, which routinely discriminates against Christians. The Telegraph reports that millions of China's Protestants worship in illegal 'house churches,' and the World Watch List ranks China as the 37th worst country in the world for Christian persecution.
"[The government does] not trust the church, but they have to tolerate or accept it because the growth is there," one house church leader told The Telegraph. "The number of Christians is growing – they cannot fight it."
Some Christians in China are coming out into the open, however. In early April thousands of Christians in Wenzhou, China formed a human shield around their church when the government threatened to bulldoze the building.
"A church is a sacred place and we are all brothers and sisters," protestor Jin Yufu told The Telegraph. "Christianity has made a big contribution to society in many ways."