19-19-302. Officer's contribution deducted from salary. The treasurer of an incorporated city that has a police retirement fund shall retain from the monthly salary of each police officer on the active list a sum equal to 6% of the officer's monthly compensation for services as a police officer, exclusive of overtime and payments made in lieu of sick leave and annual leave. The monthly deduction from the salaries of police officers must be paid into the city's police retirement fund for the purpose of paying the salaries of police officers on the retired list.