The governing body shall deduct from the salary of the tax collector, tax assessor, revenue commissioner, license commissioner, or other elected official charged with the assessment or collection, or both, of any ad valorem taxes of the county, if the officials are paid by salary, an amount equal to seven percent of the annual salary paid the official by the county. The sum shall be deducted monthly and distributed at the end of the fiscal year on a pro rata millage basis to the state, county, and all subdivisions and agencies thereof, except municipal corporations, to which ad valorem taxes are paid. If the officials are compensated by fees and commissions, the tax collector shall deduct from the money paid to the tax collector, tax assessor, revenue commissioner, license commissioner, or other elected official charged with the assessment or collection, or both, of ad valorem taxes, an amount equal to seven percent of the sum paid, and the amounts shall be distributed immediately to the state, county, and all subdivisions and agencies thereof, except municipal corporations, to which ad valorem taxes are paid. If any person coming under this chapter shall end his or her tenure of office prior to becoming supernumerary as provided in Section 40-6-1, the official whose tenure of office has ended may elect to have the total amount paid by him or her refunded or, if qualified by length of service but not age, may elect to wait until reaching age 60 and then receive the annual salary as provided for in Section 40-6-3. In the event the person dies in office prior to becoming supernumerary, and leaves no surviving spouse, the amount paid in by him or her shall be paid to his or her estate. Any surplus remaining from contributions made by a supernumerary official who dies after becoming supernumerary, and without leaving a surviving spouse, but before he or she has drawn out as much as he or she had paid in prior to becoming supernumerary, shall be paid to his or her estate. In the event an official dies in office prior to serving the minimum length of time to qualify as a supernumerary, and leaves a surviving spouse, the amount paid in by him or her shall be paid to the surviving spouse. Any person desiring to come under this chapter pursuant to subdivisions (a)(2) or (b) of Section 40-6-1, shall pay to the county tax collector such proportionate sum as to equal the amount he or she would have been required to pay if he or she were employed as a tax collector, tax assessor, revenue commissioner, license commissioner, or other elected or appointed official charged with the assessment or collection, or both, of ad valorem taxes of the county, and the proportionate sum shall be distributed by the tax collector as provided in this section.