According to CUNY's definitive American Religious Identification Survey (ARIS), the number of "Nonreligious" American adults more than doubled between 1990 and 2001 while the number of "Religious" and "Christians" declined. The "Nonreligious" are now the fastest growing segment of the population, a trend verified by results of the 2008 survey.
1990* 2001** 2008***
NONRELIGIOUS 8% (14.3 million) 14.3% (29.4 million) 15% (34.1 million)
Religious 90% 81% 79.8%
Christian 86% 77% 76%
Mormon/LDS 1.4% (2.5 million) 1.3% (2.7 million) 1.4% (3.1 million)
Jewish 1.8% (3.1 million) 1.3% (2.8 million) 1.2% (2.6 million)
Muslim/Islamic 0.3% (0.5 million) 0.5% (1.1 million) 0.6% (1.3 million)
Refused to reply 2.3% 5.4% 5.2%
Regarding religious affiliation, the authors of the 2001 survey note:
"Often lost admidst the mesmerizing tapestry of faith groups that comprise the American population is also a vast and growing population of those without faith. They adhere to no creed nor choose to affiliate with any religious community. These are the seculars, the unchurched, the people who profess no faith in any religion.
". . . the present survey has detected a wide and possibly growing swath of secularism among Americans. The magnitude and role of this large secular segment of the American population is frequently ignored by scholars and politicians alike."
ARIS survey shows 16% of Americans are "secular"
Regarding religious views, the authors of CUNY's 2001 survey note:
"In all, sixteen percent (16%) described their outlook as secular or somewhat secular while seventy-five percent (75%) described their outlook as religious or somewhat religious. . . . [A]t least ten percent of the population clearly and unambiguously considers itself 'secular' rather than 'religious.' Another six percent regard themselves as 'somewhat secular.'"
Overall, the authors note:
"The greatest increase in absolute as well as in percentage terms has been among those adults who do not subscribe to any religious identification."
* 1990 National Survey of Religious Identification (NSRI). 113,000+ samples
** 2001 American Religious Identification Survey (ARIS). 50,000+ samples
2001 American Religious Identification Survey (ARIS). 50,000+ samples Graduate Center, City University of New York
*** 2008 American Religious Identification Survey (ARIS). 220,000+ samples
Trinity College, Hartford New York