According to a just-published analysis of the 2010 Religion Census, fewer than 50% of Americans are "adherents" of Christianity. The percentage who would self-identify as "Christian," regardless of church membership and attendance patterns, is presumably higher.
The researchers define adherents to be those with an affiliation to a congregation including children, members and attendees who are not members, and believe that the adherent measure is the most complete and comparable across religious groups. Congregations are defined as groups of people who meet regularly at a pre-announced time and location. More than 150.6 million Christian adherents and 344,894 congregations were reported across the country. It is noteworthy that less than 50 percent of of the nation's population identified as Christian adherents. With close to 15.8 million Christian adherents, California reported the highest number of Christian adherents, whereas Vermont reported the lowest -- only 200,000 identified as Christian adherents. Around 10 percent of the nation's Christians reside in California. With 27,248 congregations, Texas reported the highest number of congregations in a state, whereas District of Columbia reported the lowest with 566.The above-linked reports offer no insight as the number of Americans who consider themselves atheist, agnostic, anti-theist, or merely "unchurched."