From THE NATIONAL CATHOLIC REPORTER:
The number of people who have left the Catholic church is huge.
The U.S. Religious Landscape Survey by the Pew Research Center’s Forum on Religion & Public Life has put hard numbers on the anecdotal evidence: One out of every 10 Americans is an ex-Catholic. If they were a separate denomination, they would be the third-largest denomination in the United States, after Catholics and Baptists. One of three people who were raised Catholic no longer identifies as Catholic.
Pew’s data shows that those leaving the church are not homogenous. They can be divided into two major groups: those who become unaffiliated and those who become Protestant. Almost half of those leaving the church become unaffiliated and almost half become Protestant.