(CNN) American religious affiliation has declined in small but measurable ways over the past few years, according to a new religious survey released by the Pew Research Center on Tuesday, and those changes are trickling down to the voting booth.

A growing portion of young, religiously unaffiliated individuals are driving changes in Americans' religious attitudes, reshaping the religious composition of both the Democratic and Republican parties, with the potential for policy position changes as a result, according to the survey.

The latest data from Pew shows a slight decline in religious affiliation and belief in God among U.S. adults between 2007 and 2014. The decline is largely attributable to a growing minority of young adults that don't identify with a particular religious affiliation.

More Democrats than ever describe themselves as religiously unaffiliated, representing a larger share of Democratic voters than any other religious denomination.

These religiously unaffiliated adults, referred to by the Pew survey as "nones," still largely believe in God (61% say so), but they are less likely than older, religiously affiliated individuals to pray daily, attend religious services, believe in God, or say religion is very important in their lives. And the gap is growing.

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