Muslims are on track to become the worlds fastest-growing major religious group in the years ahead, according to a new analysis of data from the Pew Research Center.

Christians make up the largest religious group in the world, at 2.3 billion people. Muslims make up the next biggest group, at just under 2 billion. But the global Muslim population is relatively young, with a high fertility rate and a low death rate.

In an analysis released Wednesday, Pew estimates that in the five-year period between 2030 and 2035, the Muslim birth rate will overtake the birth rate among Christians, with 225 million babies born to Muslim families in those years, compared to 224 million among Christians.

From that point, the birth gap is only expected to increase. Between 2055 and 2060, Pew estimates, there will be 232 million births among Muslims compared to 226 million births among Christians.