Originally Posted by John C. Ratliff

...Continued

.... The 85% figure can be valid, and represent a population this is different in age, sex, the physical environment, etc., so that another population can also have a valid figure of 35%. Helmets themselves differ over time, and that can figure into the result, as can whether a lot of children are involved...

This is about as good as I can do right now... this will be my last long post in a while.

John