Statistics of the world’s religions are only very rough approximations. Aside from Christianity, few religions, if any, attempt to keep statistical records; and even Protestants and Catholics employ different methods of counting members. The table that follows may not therefore be completely accurate, but this is what infoplease.com says about the world’s most numerous organised religions.

NOTES: As of mid-2004. This list includes only organized religions and excludes more loosely defined groups such as Chinese or African traditional religions.

Source: Encyclopaedia Britannica, taken from: http://www.infoplease.com/ipa/A0904108.html