There’s surprisingly little data available on the subject. But a 2012 poll by WIN/Gallup International — an international polling firm that is not associated with the D.C.-based Gallup group — asked more than 50,000 people in 40 countries whether they considered themselves “religious,” “not religious” or “convinced atheist.” Overall, the poll concluded that roughly 13 percent of global respondents identified as atheists, more than double the percentage in the U.S.

The highest reported share of self-described atheists is in China: an astounding 47 percent. Faith has a complicated history in China. The state is deeply skeptical of organized religion, which it has long considered a threat to its authority.

In the Taiping rebellion of the 19th century, a religious cult started a Chinese civil war that killed millions of people and left the country exposed to European powers. The official ideology of the Communist government scorned both “new” Western religions and more traditionally Chinese faiths, destroying countless temples and relics during the Cultural Revolution of 1967 to 1977. While today’s Chinese leaders do not seem to share Mao Zedong’s fervent belief that China’s rich religious history was holding it back from modernity, nor do they seem prepared to bring that history back.

Japan, where 31 percent call themselves atheist, is a little more complicated. While superficial religious observation is common – many weddings take place in churches – formal religious practice has never really recovered from the imperial era that culminated with World War Two.