Under the provisions of the City of Durango Charter, Article IV, Section 21, the aggregate amount of bonds or other forms of indebtedness payable in whole or in part from the proceeds of ad valorem taxes, or to which the full faith and credit of the City are pledged (excluding such debt relating to water and excluding securities issued under Section 23) shall not exceed 10% of the assessed valuation of the taxable property within the City, as shown in the most recent assessment for the City.