How to read this data:
In 2017, the city of St. Louis ranked #1 in violent crimes as measured for every 100,000 citizens.
List of United States cities by crime rate from Federal Bureau of Investigation (2017) for the top 100 most populous cities in America that have reported data to the FBI UCR system.
NOTE: this data is reported by each respective jurisdiction.
Just like anything else, no data set is perfect. Criticism of ranking crime data.