<human>:  What crime has the most unsolved cases on average?
<bot>: The majority of unsolved crimes are theft offenses, such as burglary or robbery. These account for approximately 40% of unsolved cases in the US, followed by homicides at 26%, and rapes at 17%. Unidentified remains account for 4% of open cases, and other offenses, such as arson or motor vehicle theft, make up a further 7%.