The percentage of Americans under 30 who doubt the existence of God appears to be growing quickly, according to a recent Pew Research Center survey, CNN reports. While most young Americans -- 68 percent -- told Pew they never doubt God's existence, that's a 15-point drop in just five years. In 2007, 83 percent of American millennials said they never doubted God's existence. No other generation showed a change of more than 2 percent in the past five years when asked about doubts of God. The survey found that the percentage of millennials who identify with a religion is remaining constant, while most other generations have seen religious affiliation increase in the past 10 years. "Research on generational patterns shows this is not merely a life-cycle effect," the Pew report said. "The millennial generation is far less religious than were other preceding generations when they were the same age years ago."