That matches my own observations, I think. Although Im not from the US. Ive got a lot of younger cousins and would be hard pressed to find any of them that are openly religious.
Also: What the hell are "millennials"? I havent heard the term before. This study seems to be talking about people born between 1988 and 1994... I could understand people born around 2000 being called "millennials", but why are people born in the '80s millennial?