The XLV was developed for use in the study of rape in American society. It used 12 indicators in three broad categories: mass media preferences as indicated by magazine circulation and viewership of certain television programs, governmental use of violence such as corporal punishment in schools, and participation in socially approved violent activities like hunting and football. The XLV enables the cumulative effect of all the independent indicators to be included in the analysis. When the index is adjusted for the percentage of single males in the population and the proportion of the population living in major urban areas, it is significantly associated to variables like the rape rate. The computations used a variety of data sets dating from 1882 to 1980. The analysis of data shows substantial differences among states and regions. Western states tend to have the highest levels of legitimate violence, and northeastern states the least. Data tables and detailed explanation of methodology.