According to new research from the Center for the Study of Global Christianity one out of five non-Christians in North America does not "personally know" a single follower of Christ. That's 13,447,000 people who don't have a Christian friend or even acquaintance. The percentages get higher for certain religious groups. For instance, 65 percent of Buddhists, 75 percent of Chinese people, 78 percent of Hindus, and 43 percent of Muslims in America do not personally know a follower of Christ.

Worldwide, the numbers are much worse: more than 8 in 10 non-Christians do not personally know a follower of Christ.

Todd M. Johnson, one of the researchers for the study, said that relatively small gestures—like inviting families into your home for Thanksgiving dinner—can have a bigger impact than huge mission campaigns. Johnson said, "You should really have lifelong friendships with Hindus, Buddhists, and so on. It's so simple, and yet it becomes a great deal."