Each such supernumerary sheriff shall serve for life and receive from the county governing body in equal monthly installments, on the first of each month, an annual salary of 50 percent of the salary of the current Sheriff of Marengo County, which shall be adjustable in like manner with any salary increase the current sheriff shall receive. For every year served as sheriff over 16 years the salary of the supernumerary sheriff shall increase by two percent of the sheriff's salary at the time he or she ceased to serve as sheriff up to a maximum of 62 percent of such salary. The tax collector, if there is a supernumerary sheriff in Marengo County, shall out of the first money collected by him or her pay to the county governing body the sum which shall be paid to the supernumerary sheriff as heretofore set forth. The sum shall be deducted on a pro rata millage basis from payments to the state, county, and all subdivisions and agencies thereof except municipalities to which the person collecting ad valorem taxes is charged with distributing of ad valorem taxes collected under the law. Should such supernumerary sheriff die or otherwise become disqualified as such supernumerary official, any money remaining in such fund shall be refunded to the person by whom it was paid to the county and he or she shall distribute the money refunded to him or her to the state, county, and other subdivisions and agencies on the same pro rata millage basis that it was originally withheld.