Nevertheless, severe problems exist in the interpretation of official data on crime compiled in different eras. However, the data for homicide are probably more accurate than the data for other crimes, although definitions of homicide have changed over time. Changing social values also affect the recording of violent crimes like assault, sexual assault, and robbery. Medieval records in England indicate that interpersonal violence was a recurring fact of rural and urban life. Oxford had the highest homicide rate estimated for any medieval English jurisdiction, with 110 murders per year per 100,000 population. In contrast, Detroit had the highest rate in the United States and Europe in 1986, with 59 per 100,000. During the 6 intervening centuries, short-term increases in violent crime occurred during times of social unrest, war, and in the early stages of industrialization. However, the long-term trend was downward. In most European nations violent crime reached its lowest recorded levels in the second quarter of the 20th century. Beginning no later than the 1970's, however, violence and robbery surged upward in almost every Western nation. Figures and reference notes.