This study, published in the American Journal of Industrial Medicine, found that overall, there was a significant decline in the rates of occupational homicide of approximately 6% per year during the study time period (1993 – 2002); this decline was found to be statistically greater than the decline of all U.S. homicides (5% per year). However, the study found that the declines have not occurred uniformly across demographic and occupational categories. Type IV workplace homicides—that is, those involving a personal relationship between the worker and the offender—have actually declined significantly less than overall workplace homicides and declined the least of the four types.