According to WIN-Gallup International’s Global Index of Religiosity and Atheism, a survey of fifty thousand people in fifty-seven countries, 13 percent of the world’s population identified themselves as a “convinced atheist” in 2012, up from around 10 percent in 2005. It would not be fanciful to say that over the course of the 20th century the global rate of atheism increased by a factor of 500, and that it has doubled again so far in the 21st. An additional 23 percent of the world’s population identify themselves as “not a religious person,” leaving 50 percent of the world as “religious,” down from close to 100 percent a century before.

Steven Pinker, Enlightenment now: the case for reason, science, humanism, and progress, New York, 2018, p. 435