Given their hostility to labels, maybe we should have called millennials "Generation X."

A survey from Pew Research that offers national detail on global religious trends shows that Americans are increasingly identifying themselves as religiously unaffiliated. Since 2007, the number of Americans who don't identify with a religious tradition rose from 16.1 to 22.8 percent -- the biggest change of any group that Pew studied.

The group most likely to identify as unaffiliated? Millennials -- those born after 1980. (Pew's definition of the generations is used below for consistency, but we remind you that the definitions are subjective. They also break out older and younger millennials; the figures are similar enough for the chart below that we just used the former category.)

The younger the group gets, the more likely it is to declare independence from organized religious groups.

That chart may look familiar. In April, Pew also looked at the party identification of the generations.

The same pattern holds.

There's overlap between the two, as well. In April, Pew found that white evangelical Protestants had grown increasingly Republican, with 68 percent identifying as or leaning Republican. That's a group that fell one percentage point, making up just over a quarter of the population in the new religion survey. The unaffiliated are a slightly smaller segment of the population -- and skew much more heavily Democratic. Sixty-one percent identified or leaned toward the party.

More than half of Americans lie in the religious middle, identifying mostly with other Christian faiths. Pew's data suggests a slow trend away from that majority, with the number of people identifying as Christian falling 8 percent in seven years.

But, again, it's young people who are driving the change. "While many U.S. religious groups are aging, the unaffiliated are comparatively young – and getting younger, on average, over time," the Pew report reads. "By contrast, the median age of mainline Protestant adults in the new survey is 52 (up from 50 in 2007), and the median age of Catholic adults is 49 (up from 45 seven years earlier)."

Meaning that whatever generation follows the millennials might be the least religious and least partisan we've ever seen.