The study covered only licensed drivers.
In all these cases, the law covers drivers from out of state.
Premiums on high-insurance vehicles soared by 80 per cent earlier this year and many companies are extremely wary of covering very young drivers.
The need for new contracts covering drivers employed by the four wholesale distributors arose in recent months with the pending sale of the companies.
The Governor pledged to fix the state's automobile insurance mess and eliminate the surcharge added to everyone's premium to cover high-risk drivers.
The law covers drivers who have accepted limits on their ability to sue after an accident, under the state's no-fault insurance system.
The reason for the minimum age is that the rental companies do not carry insurance covering younger drivers, considered by the insurance companies as high-risk.
They are called "named nonowner" policies and cover drivers for liability.
Insurance companies responded by refusing to cover most young drivers and residents of densely populated, high-risk areas - fully half the drivers in the state.
The tangled dispute arose when the union rejected the contracts covering drivers at the four wholesale delivery companies.