(1) After June 30, 1989, the "pure loss component" of the final rate or premium charge for private passenger automobile insurance is that portion of the final rate or premium charge applicable to calendar/accident year incurred losses (the sum of paid losses plus loss reserves including incurred but not reported loss reserves) and loss adjustment expense (those expenses directly related to the payment of claims) in this State, trended to include both the past and prospective loss experience. If the insurer writes one percent or more of the written premium for automobile insurance during the previous calendar year, that insurer must file its own trending methodology as independently derived.

(2) The "expense component" of the final rate or premium charge for private passenger automobile insurance is that portion of the final rate or premium charge applicable to production costs (including commissions and other acquisition expenses), underwriting costs, administrative costs (including the actual costs of taxes, licenses and fees), and profit margin in this State.

(3) The "final rate or premium charge" is the approved pure loss component added to the approved expense component. In the determination of whether the pure loss component should be approved and in the determination of whether the expense component should be approved, neither may be inadequate, excessive, nor unfairly discriminatory and the director or his designee shall take into account investment income from unearned premium and loss reserves, surplus and realized capital gains.