The contingent expenses of the Prosecuting Attorney for the Fourteenth Judicial District shall be limited to the sum of seven thousand eight hundred dollars ($7,800) per annum, to be paid quarterly and to be borne by the counties of the district as follows:
(1) Baxter County (36% by population) $2,808;
(2) Boone County (36% by population) 2,808;
(3) Marion County (16% by population) 1,248; and
(4) Newton County (12% by population) 936.