Cia world Facebook- 5 major religions

Using the CIA world Factbook I was able to rank 5 major religions of the world by the percent of the worlds population that follow them. Then I used adherents.com in order to see if the percentages are consistent. On CIA world Factbook I found that 31.4% of the world follow Christianity, 23.2% are Muslim, 15% are Hindu, 7.1% are Buddhist, 5.9% are folk religion, 0.2% Jewish and 16.4% who don't identify as having a religion. On Adherents.com I found that 33% are Christian, 21% Islam, 16% non-religious, 14% Hindu, 6% primal-indigenous, 6% Chinese traditional, 6% Buddhism, 0.36% Sikhism, and 0.22% Judaism. In conclusion the number are pretty much the same except for a few percentage points each.