Michigan's mandatory fee to cover unlimited medical benefits for injured drivers is going up to $192 a year, an increase of $22 over the current annual fee per insured vehicle.

The Michigan Catastrophic Claims Association announcing the 13% increase, which follows a 6.3% increase in 2017.

The fee revenue largely covers care for people with brain, spinal cord, back and neck injuries.

Officials say the fee hike is due to higher-than-expected claims, partially offset by better-than-expected investment returns.