What is the fastest growing religion in the world?

[Cameron Anfang]

It is stated that the fastest growing religion is the Baha'i faith, with a growth rate of 2.3%. It is followed by non-Christian spiritist traditions with a growth rate of 2.0% and Sikhism with 1.9%. Islam is second. Christianity is by far the fastest growing but consists of many different sub-divisions. However it was according to a study conducted in 2005.

Source: https://www.quora.com/What-are-the-most-and-least-popular-world-religions

[Dakota Schaefer]

"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." 

Source: http://www.cnn.com/2015/04/02/living/pew-study-religion/