Written by by George H. Gallup Jr in 2003:
As described in The Next American Spirituality, which Tim Jones and I wrote, the pendulum may be swinging away from what is beyond us to what is within us. In the 1999 survey, we asked, "Do you think of spirituality more in a personal and individual sense or more in terms of organized religion and church doctrine?" Almost three-quarters opted for the "personal and individual" response.
In a January 2002 poll, 50% of Americans described themselves as "religious," while another 33% said they are "spiritual but not religious" (11% said neither and 4% said both).
From: http://www.gallup.com/poll/7759/americans-spiritual-searches-turn-inward.aspx
(SBNR = Spiritual But Not Religious)