In every locality of this Commonwealth, whenever the Compensation Board shall provide salary increases, including but not limited to cost-of-living increases, whether specifically for constitutional officers and their assistants or deputies or for the general compensation to be paid in the aggregate to a constitutional officer, pursuant to any statutory or other authority, no locality shall use such reimbursement for any purpose other than salary during the fiscal year. A locality shall distribute such salary in appropriate proportions to its constitutional officers and their assistants or deputies. As used in this section, “constitutional officer” means the treasurer, sheriff, attorney for the Commonwealth, clerk of circuit court, or commissioner of revenue of any locality.