In ascertaining the condition of a domestic stock property or casualty insurance company, there shall be allowed as assets only such investments, cash, and accounts as are authorized by the laws of this state at the date of the examination. In ascertaining its liabilities, there shall be charged in addition to the capital stock, all outstanding claims, and a sum equal to one hundred percent of the unearned premiums on the policies in force, after deducting credit for reinsurance authorized by sections 44-416.05 to 44-416.10, calculated on the gross sum without any deductions on any account, charged to the policyholder on each respective risk from the date of the issuance of the policy. In ascertaining the condition of a domestic mutual property or casualty insurance company, other than a company licensed solely to write the line of insurance specified in subdivision (4) of section 44-201, there shall be allowed as assets only such investments, cash, and accounts as are authorized by the laws of this state at the date of examination. In ascertaining its liabilities, there shall be charged all outstanding claims and a reserve in an amount equal to one hundred percent of the total unearned premium on all their policies in force. If the department finds this section to be impractical in ascertaining the condition of certain kinds of insurance companies, the department shall adopt and promulgate such rules and regulations as it deems proper, efficient, and consistent with law. Such rules and regulations shall give due regard to the statutes, rules, regulations, and established industry practices which may be used in other states or which are approved by the National Association of Insurance Commissioners.