What is the world's largest religious population?
List of religious populations
The CIA's World Factbook gives the world population as 7,021,836,029 (July 2012 est.) and the distribution of religions as Christian 100% (of which Roman Catholic 18.85%, Protestant 8.15%, Orthodox 4.96%, Anglican 1.26%), 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%.