Americans are some of the most religious people in the world — but a huge survey noted that the religion in question changes with astonishing frequency. A 35,000-person poll by the Pew Forum for Religion & Public Life found that 28% of U.S. adults have left their cradle faith for another one — 44% if you're talking about denominations rather than faiths. The poll suggests great national piety coupled with remarkable disdain for the multi-generational doctrinal and ethnic ties that used to define American religion.