Here's a clip from recent findings in an AP article:
A wide-ranging study on American religious life found that the Roman Catholic population has been shifting out o of the Northeast to the Southwest, the percentage of Christians in the nation has declined and more people say they have no religion at all.
Fifteen percent of respondents said they had no religion, an increase from 14.2 percent in 2001 and 8.2 percent in 1990, according to the American Religious Identification Survey.
Northern New England surpassed the Pacific Northwest as the least religious region, with Vermont reporting the highest share of those claiming no religion, at 34 percent. Still, the study found that the numbers of Americans with no religion rose in every state.