Final answer:
The approximate success rate of probationers completing supervision can be calculated by dividing the number of probationers by the total correctional population and multiplying by 100.
Step-by-step explanation:
The question is about the success rate of probationers in completing supervision. According to the Bureau of Justice Statistics, the total correctional population in the US includes parolees and those on probation. In 2018, the correction system had around 6.4 million people, resulting in a ratio of 1 in every 40 people being under some sort of correctional supervision. Therefore, the approximate success rate of probationers completing supervision can be calculated by dividing the number of probationers by the total correctional population and multiplying by 100.