Why Are Americans Are Leaving Religion Behind

Nearly half (49 percent) of the "nones" in the survey reported leaving religion because they just don't believe in it.

One fifth (20 percent) of the "nones" said they rejected their childhood religion because they dislike the organization itself.

If those two reasons seem natural and almost self-explanatory, the third explanation is where it really gets interesting.

Perhaps the most surprising cohort of the religious "nones" are the "inactive believers." They account for 10 percent of those surveyed: 8 percent described themselves as "non-practicing," and the other 2 percent said they were just "too busy." This group included zero atheists and only 3 percent of agnostics.