PRINCETON, NJ -- The large majority of Americans -- 77% of the adult population -- identify with a Christian religion, including 52% who are Protestants or some other non-Catholic Christian religion, 23% who are Catholic, and 2% who affiliate with the Church of Jesus Christ of Latter-day Saints. Another 18% of Americans do not have an explicit religious identity and 5% identify with a non-Christian religion.
Source: Gallup. Read full article. (link)