Adherents VS CIA World Fact Book

The information from adherents is a little different than the more updated information on the CIA World Factbook. This is quite ironic since the website adherents is known for having information specifically on religions. On adherents it has the percentages for 2005 at Christianity 33% of the world, Islam at 22%, Hinduism at 14%, Buddhism at 6%, and Judaism at .22%. On the CIA World Factbook it has the percentages for Christianity at 31.4% of the world, Islam at 23.2%, Hindu 15%, Buddhist 7.1%, and 0.2 for Jewish. It seems that the Christianity population has decreased, while other religions have increased by a little. Judaism has remained roughly the same, but I am still very surprised that the amount of Jewish people are so low. World War 2 had a big impact on this. Now seeing the CIA World Factbooks information is roughly updated and has so much information, I think its more of a reliable source than adherents.com.