There's a statistic that gets thrown around a lot in Youth Ministry and in Church in general. I may not remember it precisely, but it's something like 85% of people who make a decision to follow Christ do it before the age of 18. Sometimes it is more negatively stated: if I person doesn't make a decision to follow Christ by age 18, they probably never will. To be totally honest, I think this statistic is a little flawed in that it fails to take into account that most of the people it refers to probably grew up in Christian homes and Christian environments, so it really shouldn't be all that surprising for various psychological and sociological reasons. Even so, I think there may be an important truth to glean from those who decide to follow Jesus in that timeframe who did not grow up in a Christian family.
Is it possible that more people are converted through youth ministry than through the church at large? (I know that the church at large provides the youth ministry, but hear me out.) How could that be? Why would that be? Do you know what the requirements are for belonging to a youth group? You just have to want to be a part of it. Compare that with the requirements for belonging to a church. As Brian McLaren points out in several of his books, churches tend to motivate by exclusion, i.e. "do these things" and "think these things" and then you can truly belong. Youth ministry has always motivated by inclusion, i.e. "join us", "come along with us", "be a part of us"...in the hope that through belonging they may come to believe. There was a time when "motivation by exclusion" worked pretty well for churches. I wonder if that time has past. I wonder if we ever should have tried it in the first place.