The only group that shows a significant decline of "Nones" is the 55-64 age group. I think that's interesting.
But the Millennials and Generation Next young folks are no surprise a all to me. I'll be curious to see the numbers of the currently under 18 group when they reach adulthood.
I know a few in the younger two groups. The ones I know no longer see the Church as having any relevance in their lives. Most have completely stopped going, despite their parents still attending services. One 30-year-old who is a second cousin of my wife's says that she is an atheist, now. She was a steady church-goer until her mid 20s. Then, she simply stopped attending and stopped believing. About the same time she announced that she was bi-sexual, which surprised nobody. My wife and I love her dearly, and she's a regular visitor at our house, where she comes, sits down and we all talk about stuff that's relevant and current. She is remarkably open about her life to us and actually asks us for advice on things. Amazing! We're careful not to offer too much of that, though.