If you go to the people who run insurance programs, especially people who look after injuries, there's well- established information. They can look at the information and know how particular ranks progress—on average—during the course of a career. Some people might be getting out when they're 30, or whatever, but they have ways of handling these things. There is a mythology behind it that is agreed to by insurance companies.
On November 24th, 2009. See this statement in context.