(a) The Prosecuting Attorney of the Seventh Judicial District shall be entitled to a contingent expense allowance of not less than eleven thousand sixty-three dollars ($11,063) per annum to be paid by the respective counties of the Seventh Judicial District as follows:
(1) Saline County $7,463;
(2) Hot Spring County $2,400; and
(3) Grant County $1,200.
(b) Saline County may at any time increase its contribution to such contingent expense allowance.