<P> The table (below) and the pie chart list religions classified by philosophy; however, religious philosophy is not always the determining factor in local practice . Please note that this table includes heterodox movements as adherents to their larger philosophical category, although this may be disputed by others within that category . For example, Christianity and Islam include those who are culturally Christian and Muslim as well as indigenous people combining folk religions or shamanism with either . </P> <P> The population numbers below are computed by a combination of census reports, random surveys (in countries where religion data is not collected in census, for example the United States or France), and self - reported attendance numbers, but results can vary widely depending on the way questions are phrased, the definitions of religion used and the bias of the agencies or organizations conducting the survey . Informal or unorganized religions are especially difficult to count . Some organizations may wildly inflate their numbers . </P> <Table> <Tr> <Th> Religion </Th> <Th> Number of followers (in millions) </Th> <Th> Cultural tradition </Th> <Th> Founded </Th> <Th> References </Th> </Tr> <Tr> <Td> Christianity </Td> <Td> 01! 2,420 </Td> <Td> 01! Abrahamic religions </Td> <Td> Middle East </Td> <Td> </Td> </Tr> <Tr> <Td> Islam </Td> <Td> 02! 1,800 </Td> <Td> 02! Abrahamic religions </Td> <Td> Middle East </Td> <Td> </Td> </Tr> <Tr> <Td> Hinduism </Td> <Td> 03! 1,150 </Td> <Td> 03! Indian religions (Dharmic) </Td> <Td> Indian subcontinent </Td> <Td> </Td> </Tr> <Tr> <Td> Buddhism </Td> <Td> 05! 520 </Td> <Td> 05! Indian religions (Dharmic) </Td> <Td> Indian subcontinent </Td> <Td> </Td> </Tr> <Tr> <Td> Folk religion </Td> <Td> 04! 400 </Td> <Td> 04! Organized religion </Td> <Td> Worldwide </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Religion </Th> <Th> Number of followers (in millions) </Th> <Th> Cultural tradition </Th> <Th> Founded </Th> <Th> References </Th> </Tr>

What is the main religion in the world