for the interest and redemption of all outstanding bonds of the authority, as provided by Section 1 of Article XIII A of the California Constitution. The tax shall not be less than sufficient to pay the interest on the bonds as it becomes due and to provide a sinking fund for the payment of the principal payable or on before maturity and may include an allowance for an annual reserve, established for the purpose of avoiding fluctuating tax levies. The tax shall be sufficient to provide funds for the payment of the interest on the bonds as it becomes due and also any part of the principal and interest that is to become due before the proceeds of a tax levied at the time for making the next general tax levy may be made available for the payment of the principal and interest.