Islam, the world’s fastest-growing faith, will leap from 1.6 billion (in 2010) to 2.76 billion by 2050, according to the Pew study. At that time, Muslims will make up nearly one-third of the world’s total projected population of about 9 billion people.

Christianity is expected to grow, too, but not at Islam’s explosive rate. The Pew study predicts Christians will increase from 2.17 billion to 2.92 billion, composing more than 31% of the world’s population.

This means that by 2050, more than 6 out of 10 people on Earth will be Christian or Muslim. And, for perhaps the first time in history, Islam and Christianity would boast roughly equal numbers.