Fewer Religious in the US?

This story, citing a Pew study, makes the welcome claim that religion in America is waning.

As an addendum, I've often wondered what one could say about the historical impact of religion in hampering economic and intellectual development, and thereby promoting or enabling a class-divided society.  My biggest data point was the relative rise of North America vs. South America, despite the latter having many initial advantages in wealth and resources. (Christianity was hammered into the South Americans, but thanks to men like Jefferson and Madison that wasn't really the case in the US.)  Nonetheless, there was a push in America to make slaves religious, and it seems to have seeped into the black culture as this data point might suggest:

A new study released on Tuesday by the Pew Forum on Religion and Public Life found that it was not just liberal mainline Protestants, like Methodists or Episcopalians, who abandoned their faith, but also more conservative evangelical and “born again” Protestants. The losses were among white Protestants, but not among black or minority Protestants, the study found, based on surveys conducted during the summer. (my emphasis)

(Please note that I'm not denying that the choice of accepting religion or not is a matter of an individual's free will, it's just that in certain cultures many never come across the arguments or develop the thinking tools necessary to  make an educated choice in the matter.   In those cases the trend and the concerted push by the cultural authorities will generally hold sway.)