It's not 2-26% remaining uninjured. It is 2%-26% reduction of an already very small number. I reject the reasoning that any given safety measure is automatically justified by any reduction of risk no matter how small. If I thought that, I wouldn't ride at all.

I don't want to talk any adult out of wearing a helmet, nor insist that they should wear one. I do want them to have the information necessary to evaluate their risk, to make their own decisions. Too often the risk is overstated, and the effectiveness of helmets exaggerated. It's often stated that helmets reduce head injury by 85%, and that claim has been conclusively refuted and retracted.