Muslims participate in a Friday prayer November 14, 2014, at the National Cathedral in Washington, DC. Alex Wong/Getty Images

There were 3.3 million Muslims of all ages living in the United States in 2015, or about 1 percent of the total U.S. population, the Pew Research Center reports. The figure is an update to Pew’s 2011 estimate of 2.75 million Muslims living in the United States. By 2050, Pew expects the share of Muslims in the U.S. to double to 2 percent.

“Recent political debates in the U.S. over Muslim immigration and related issues have prompted many to ask how many Muslims actually live in the United States,” writes Basheer Mohamed, a senior researcher at Pew. “But coming up with an answer is not easy, in part because the U.S. Census Bureau does not ask questions about religion, meaning that there is no official government count of the U.S. Muslim population.”

Pew based its new figure on a demographic projection that bases growth on age, fertility, mortality, migration and religious switching figures from multiple sources. It first estimated the size of the American Muslim population in 2007.

Projected population growth of Muslims in the United States Pew Research Center

According to Pew, the U.S. Muslim population is smaller than the Jewish population of 5.7 million. But it’s larger than the Hindu population of 2.1 million. Pew also expects the Muslim population to grow faster than both the Jewish and Hindu ones in the coming years. By 2040, Muslims will likely become the second-largest religious group in the United States after Christians. By 2050, Pew estimates that there will be 8.1 million Muslims living in the country, or about 2.1 percent of the total population.

More than half of the increase in the Muslim population between 2010 and 2015 has been due to immigration. Muslim immigrants currently make up about 10 percent of all legal immigration to the United States. But Muslims also tend to have more children than other Americans, which also accounts for part of the community’s growth. Conversion, however, has not been responsible for the increase. About 20 percent of American Muslim adults converted from another faith, but that figure has not changed over time.