Catholic League president Bill Donohue explains why the Catholic League is starting a new initiative aimed at atheists:

Approximately 80 percent of Americans are Christian, and 96 percent celebrate Christmas. Of the 20 percent who are not Christian, non-believers make up the largest segment, though the number of self-identified atheists is tiny. David Silverman, president of American Atheists, knows this to be true, which is why he is frantically trying to inflate his base. “We want people to realize that there may be atheists in their family,” he told the New York Times, “even if those atheists don’t even know they are atheists.”

http://www.catholicleague.org/adopt-an-atheist-campaign-begins/