Figure 7.5 Major religions of the world. The world’s major religions, by numbers of adherents expressed as a percentage. The third largest religious group in the world is, in fact, composed of those who are not affiliated with any established faith. Note that though Judaism is a prominent religion in the United States, it does not rank among the major world religions in terms of total number of adherents. (Source: Pew Research Center’s Forum on Religion and Public Life, Global Religious Landscape, 2012.)