From Ed Stetzer’s research at LifeWay, and at the link you can read a fuller report about this study:
When it comes to discipleship, churchgoers struggle most with sharing Christ with non-Christians according to a recent study of church-going American Protestants.
The study conducted by LifeWay Research found 80 percent of those who attend church one or more times a month, believe they have a personal responsibility to share their faith, but 61 percent have not told another person about how to become a Christian in the previous six months.
These distressing results came from an extensive discipleship research project focused on measuring spiritual maturity in individuals. Overall, LifeWay Research found eight biblical attributes consistently evident in the lives of maturing believers. Of those eight, “Sharing Christ” has the lowest average score among Protestant church attendees.