Library of World Religions and Spirituality

If you've ever wondered how many are in the various religious groups, here's a good chart.

Library of World Religions and Spirituality | Faith | Patheos

At this time, Christians (2.1 billion) outnumber Muslims (1.5 billion), but when they take over a piece of land, say, near Ground Zero to build a mosque, or a convert who later converts to Christianity, there's never a reversal in their view, so that could change.