Except where such a charge would be inconsistent with federal law, gross premiums include all premiums and premium deposits and assessments on all policies, certificates, and renewals, written during the year, covering property and risks within the state, policies subsequently cancelled, and reinsurance assumed, whether the premiums and premium deposits and assessments are in the form of money, notes, credits, or other substitute for money, after deducting from the gross premiums the amount of return premiums on the contracts covering property and risks within this state and the amount of premiums for reinsurance assumed, of the property and risks. Mutual companies and companies which transact business on the mutual plan are also allowed to deduct from their premiums and premium deposits and assessments, the so-called dividends or unused or unabsorbed portion of the premiums and premium deposits and assessments applied in part payment of the premiums and premium deposits and assessments or returned to policyholders in cash or credited to policy holders during the year for which the tax is computed. Every domestic company, mutual association, organization, or other insurer, shall include for taxation in like manner and with like deductions premiums and premium deposits and assessments written, procured, or received in this state on business covering property or risks in any other state on which the company has not paid and is not liable to pay a tax to the other state.