On the subject of injuries from dangerous manual labor, I read something interesting. There was a study about how people died and they found something unexpected. The percentage of people who died from accidents remained constant over a period going back to the fourteenth century. Your odds of dying from other causes would go up and down but the odds that you would died in an accident remained steady.
On the surface this makes no sense. It would seem that if the odds of other causes changed it would be reflected in the accidental death rate. if fewer people were dying from infections, for example, that should mean more of them would live to have fatal accidents. And the potential for accidental deaths would appear to have increased; we now have cars and electricity and industrial machines that can kill us in ways our ancestors never faced. But somehow the death rate remains the same.
The theory offered was that accidents are a much more social phenomena than we consciously realize. We hear about other people dying in accidents and we unconsciously modify our behavior. If we hear about a lot of accidental deaths, we start being more careful and begin using safety features. And if we don’t hear about accidental deaths, we become less careful and take more risks. The result is the overall accidental death rate maintains an equilibrium.