The Pew Forum on Religion and Public Life has another truly outstanding report which provides detailed data on the religious affiliations of Americans today in the Continental United States (survey size of over 35,000 adults, detail to 0.3%, detail at a state or two state level available for larger categories).
The report accurately describes the major Christian subdivisions of Evangelical Protestant (26.3%), Mainline Protestant (18.1%), Historically Black (6.9%), Catholic (23.9%), Mormon (1.7%), Jehovah's Witnesses (0.7%), Orthodox (0.6%) and Other Christian (0.3%) and has a good methodology for making the distinctions in situations where answers are arguably ambiguous.
It also provides some of the best data on other religious affiliations: Jewish (1.7%), Buddhist (0.7%), Muslim (0.6%), Hindu (0.4%), Other World Religions (less than 0.3%), Other Faiths (1.2%, including Unitarian Universalists).
It is also exceptional in distinguishing within the growing ranks of the Unaffiliated (16.1%) between Atheists (1.6%), Agnositics (2.4%), the secular unaffiliated (6.3%), and the religious unaffiliated (5.8%). In addition 0.8% didn't know or refused to answer.
It has good demographic information on every category it surveys, and good, detailed information on conversion patterns from one category to another. The report also has clear charts and graphics accompanying it.
Very few of the report's findings are shocking news to anyone familiar with religious demographics (I field in which I was recently reminded that my mother was once professional employed as a demographer for a major Lutheran Church denomination in the 1960s).
The methodology Pew uses does an excellent job of distinguishing the impact of patterns of religious conversion during a person's life from impacts on church membership as a result of immigration.
For example, the decline in the ranks of Catholic church membership as a result of net conversions (conversions out mitigated by conversions in) reduced the church's membership by 24% (not percentage points), despite the fact that immigration has allowed the Catholic church to maintai steady overall membership numbers in the United States.
A net 18% of Baptists have converted away from that faith, but this is almost completely offset by the rise of Non-Denominational churches, most of which are evangelical as well, which have tripled their percentage share of the American public, and Pentecostal church affiliations (like the Assemblies of God) which have seen a 28% growth from conversions.
Data on income and faith is always interesting. The data below are abridged to show only the percentages of members of each faith tradition in the top and bottom income categories surveyed, and reordered based upon percentages in the lowest income category:
U.S. Religious Traditions: Less than $30,000 -- $100,000+
Historically Black Protestant Churches 47% -- 8%
Jehovah's Witnesses 42% -- 9%
Muslims 35% -- 16%
Evangelical Protestant Churches 34% -- 13%
National Total: 31% -- 18%
Catholics 31% -- 19%
Unaffiliated 29% -- 19%
Other Christians 29% -- 23%
Other Faiths 28% -- 18%
Mormons 26% -- 16%
Mainline Protestant Churches 25% -- 21%
Buddhists 25% -- 22%
Orthodox 20% -- 28%
Jews 14% -- 46%
Hindus 9% -- 43%
Go read it.