...as for the "local" side of things, here's the picture:
The report shows, for example, that every religion is losing and gaining members, but that the Roman Catholic Church “has experienced the greatest net losses as a result of affiliation changes.” The survey also indicates that the group that had the greatest net gain was the unaffiliated. More than 16 percent of American adults say they are not part of any organized faith, which makes the unaffiliated the country’s fourth largest “religious group.”...-30-
The percentage of Catholics in the American population has held steady for decades at about 25 percent. But that masks a precipitous decline in native-born Catholics. The proportion has been bolstered by the large influx of Catholic immigrants, mostly from Latin America, the survey found.
The Catholic Church has lost more adherents than any other group: about one-third of respondents raised Catholic said they no longer identified as such. Based on the data, the survey showed, “this means that roughly 10 percent of all Americans are former Catholics.” [Ed. Note: that stacks up to roughly 27 million.]
Immigration continues to influence American religion greatly, the survey found. The majority of immigrants are Christian, and almost half are Catholic.