Islam is the world’s fastest growing religion – and not just in Muslim majority nations: 10% of all Europeans are projected to be members of the Muslim faith by 2050, according to a recent Pew Research Center study.

The study estimates that from 2010 to 2050, Muslims will have increased across the world by 73%, followed by Christians who are projected to grow by 35% during the same time period, and Hindus at 34%.

That means that Islam — currently the world’s second-largest religion — will surpass Christianity as the world’s biggest religion by the end of the century, the study projects.

Why? Muslim women have more children, on average — 3.1 children compared to 2.3 for all other religious groups combined, Pew says. Also, those of the Muslim faith tend to be, on average, seven years younger than non-Muslims.