Certain percentages are not calculable because rate cannot be divided by zero.
Percentages show the five year trend in crime rate.
Crime rates control for differences in population, therefore the counties are comparable. Crime rates are determined by dividing the number of crimes by the population, then multiplying by 100,000. Percentage changes are determined by subtracting the number of in 1992 from the number in 1996, then dividing the total by the number of crimes in 1992. Percentages show the five year trend in crime rate. Crime rates control for differences in population, therefore the counties are comparable.