The value to be reported for each investment under the Insurance Code, Article 4.11, shall be admitted value reflected in the insurer's annual statement as of December 31 of the tax year, except demand deposits of banks, savings and loans, or other financial institutions. Such demand deposits shall be reported at the average of the month-end balance for each of the 12 months of the tax year. The month-end balances of demand deposits shall be determined from the insurer's ledger accounts. This section applies to taxes on premiums collected on and after January 1, 1985.