In all product liability actions where damages for any medical or hospital expenses are claimed and are legally recoverable for personal injury or death, evidence that the plaintiff‘s medical or hospital expenses have been or will be paid or reimbursed (1) by medical or hospital insurance, or (2) pursuant to the medical and hospital payment provisions of law governing workmen’s compensation, shall be admissible as competent evidence in mitigation of such medical or hospital expense damages. In such actions upon admission of evidence respecting reimbursement or payment of medical or hospital expenses, the plaintiff shall be entitled to introduce evidence of the cost of obtaining reimbursement or payment of medical or hospital expenses. Such portion of the costs of obtaining reimbursement or payment of medical or hospital expenses as the trier of fact finds is reasonably related to the reimbursement or payment received or to be received by the plaintiff shall be a recoverable item of such damages for medical or hospital expenses.