The regular interest charges payable, the creation and maintenance of the necessary reserves for the payment of the county and members' annuities in accordance with this act, and the additional retirement benefits, are hereby made obligations of the county. The board shall prepare and submit to the county commissioners, on or before the first day of November of each year, an itemized estimate of the amounts necessary to be appropriated by the county to complete the payment of the obligations of the county during the next fiscal year.