In addition to the salary now paid by the state to the judge of the Thirty-fifth Judicial Circuit, and in addition to the salary now paid by the state and by the respective counties composing the circuit to the official court reporter, there shall be paid to the judge a salary supplement in the amount of ten thousand dollars ($10,000) per annum, to be paid in equal monthly installments, and to the official court reporter a salary supplement in the amount of five thousand dollars ($5,000) per annum, to be paid in equal monthly installments. The supplements provided for herein shall be paid from the general funds of the counties composing the circuit on a pro rata basis calculated upon the assessed value of taxable property in the counties of the circuit for the previous fiscal year, as shown by the records of the tax assessors' offices, in such manner that each county shall pay such proportion of the supplements as the assessed value of the property in the county bears to the total assessed value of all property within the counties composing the judicial circuit.