Which religion is the most popular in the world?
The CIA's World Factbook gives the distribution of religions as Christian 33.39%, Muslim 22.74%, Hindu 13.8%, Buddhist 6.77%, Sikh 0.35%, Jewish 0.22%, Baha'i 0.11%, other religions 10.95%, non-religious 9.66%, atheists 2.01%. (2010 est.)