I believe the answer is: 15-19 years old
The high number is caused by incompetent skills and driving under influence which seems more prevalent on this age group.
If put into a comparison, drivers within the age of 15-19 years old is 3 times more likely to be involved in an accident compared to the drivers that are 20 years old or older.
Because they are excellent objectives indicators of students performance.
alcohol usage, abusive behavior, relationships, ect.
You do summer school or get stay in the same grade as before