 that State Farm's premium was structured to charge more for the increased risk borne by the company as a result of providing personal coverage to additional drivers. Although the Penningtons received UIM coverage for four drivers, their premium was not simply a multiplier of coverage (e.g., multiplying the base premium rate by the number of drivers). Rather, if a multiplier of coverage had been used, the family would have been charged four times the base premium for the four drivers in the household. 