Why should you wear a seat belt?

I have a friend who will not wear his seat belt. He thinks he can react fast enough to avoid being hurt in any sort of crash. He also thinks he is invincible and won't end up in an accident in the first place. Does anyone know of any articles or resources I could use to convince him otherwise? He has never been in an accident before and doesn't realize how quick they happen. It's impossible to convince him to wear one, but maybe if I have some statistical data and research I can. Please help.