According to numbers released by the Bureau of Labor Statistics late in 2012, workplace injuries continue to decline:
* The injury rate for public sector workers is higher — 5.7 cases per 100 full-time workers. Rates are much higher in local compared to state government work.
The declining rates continue the dramatic progress made in the twentieth century:
* Between 1900 and 1970, “the number of fatalities per dollar of real (inflation-adjusted) GNP dropped by 96 percent.”
* “Since 1970, workplace fatalities have been reduced by more than 65 percent and occupational injury and illness rates have declined by 67 percent. At the same time, U.S. employment has almost doubled.”
The key factors: technology, economic incentives such as wage premiums, increased knowledge, improved medical care, regulation, and litigation have all played a role. I don’t know of any good sources that quantify the contribution of each factor.