Further, it has a high crime index much of which is violent crime. (biggerpockets.com)
(Note that the combined crime index of all precincts totals 600, because the percentage for each crime type adds up to 100 percent citywide, and we are combining six categories.) (scientificamerican.com)
Thus, if in 1990 precinct X had 4 percent of all homicides, 4 percent of all rapes, and so on for each of the other four types of crime, the combined crime index for that precinct would be: (scientificamerican.com)