No county shall hereafter issue bonds secured by a pledge of its full faith and credit for the purposes authorized by law in an amount which, when added to the then outstanding bonds of such county, shall exceed either (a) fifteen percent (15%) of the assessed value of the taxable property within such county according to the last completed assessment for taxation, or (b) fifteen percent (15%) of the assessment upon which taxes were levied for its fiscal year ending September 30, 1984, whichever is greater.

However, any county in the state which shall have experienced washed-out or collapsed bridges on the public roads of the county for any cause or reason may hereafter issue bonds for bridge purposes as now authorized by law in an amount which, when added to the then outstanding general obligation bonds of such county, shall not exceed either (a) twenty percent (20%) of the assessed value of the taxable property within such county according to the last completed assessment for taxation or (b) fifteen percent (15%) of the assessment upon which taxes were levied for its fiscal year ending September 30, 1984, whichever is greater.

Provided further, in computing such indebtedness, there may be deducted all bonds or other evidences of indebtedness heretofore or hereafter issued, for the construction of hospitals, ports or other capital improvements which are payable primarily from the net revenue to be generated from such hospital, port or other capital improvement, which revenue shall be pledged to the retirement of such bonds or other evidences of indebtedness, together with the full faith and credit of the county. However, in no case shall any county contract any indebtedness payable in whole or in part from proceeds of ad valorem taxes which, when added to all of the outstanding general obligation indebtedness, both bonded and floating, shall exceed either (a) twenty percent (20%) of the assessed value of all taxable property within such county according to the last completed assessment for taxation, or (b) fifteen percent (15%) of the assessment upon which taxes were levied for its fiscal year ending September 30, 1984, whichever is greater. Nothing herein contained shall be construed to apply to contract obligations in any form heretofore or hereafter incurred by any county which are subject to annual appropriations therefor, or to bonds heretofore or hereafter issued by any county for school purposes, or to bonds issued by any county under the provisions of Sections 57-1-1 through 57-1-51, or to any indebtedness incurred under Section 55-23-8, or to bonds issued under Section 57-75-37 or to any other indebtedness incurred under 57-75-37(4).