Does anyone have the stats on how many lives seatbelts do not save or make no difference in saving?

This being 'Ticket or click it" weekend, you hear about the very few lives that seatbelts save. I want to know about the lives lost to seatbelts or the lives where the seatbelt made no difference in saving. I have seen far more accidents where the seatbelt has bruised, broken, or removed body parts and no threat to life was present. I have seen Suplemental Restraint Systems break peoples jaws and femurs. So, which it? Saves lives, makes no difference, takes lives.