provided, however, that if a county's population decreases according to a more recent census below its population according to an earlier census, then, notwithstanding any other provision of law, any officer who is compensated under a law specified in this subparagraph and who is in office on the date specified in this subparagraph shall continue during his or her entire tenure in such office (including any future terms of office in such office) to be compensated on the basis of the county's population according to such earlier census;
OCGA § 1-3-1