A few quick tidbits of note from Summary of Key Findings:
16% are not affiliated with any denomination. That's more than double the number who said that they were unaffiliated when they were children.There are interactive charts and graphs breaking down the whole study at this link. Have fun. Come to you own conclusions.
Protestants will soon be in the minority. They make up currently 51% of the population and that is broken up into hundreds of denominations. The largest group of denominations are evangelicals which make up 26.3% of all protestants.
While American born and raised Catholics are changing affiliations in larger numbers than any other religion, the influx of Catholic immigrants makes up for it.