I am not totally convinced there has been such a great sea-change in religious attitudes here in the U.K as has been reported, based on recent Polls.
I think one reason the Non-religious seem to have more numbers now is that people are more honest about it than a few decades ago, many would have then answered "CofE" or something similar, Methodist say, because their family had a history of affiliation, but these people were far from regular church-goers, and far from being believers in their own minds in anything more than a vague way.
I wonder if something similar is not at work in the Pew Research findings.
There are interesting pockets of non-belief in Europe, the Czech Republic and the Netherlands for example, and it is heartening to see that at least 13% of U.K citizens identify as Atheist.
There is still much educational work to be done to free people from the ignorance that keeps them in religions like Islam, Catholicism, Mormonism, the J.W's etc