For the purpose of providing moneys in said judges' retirement fund, concurrent monthly deductions from judges' salaries and portions thereof payable from the state treasury and withdrawals from the general fund of the state treasury shall be made as follows: Six and one-half percent shall be deducted from the monthly salary of each justice of the supreme court, six and one-half percent shall be deducted from the monthly salary of each judge of the court of appeals, and six and one-half percent of the total salaries of each judge of the superior court shall be deducted from that portion of the salary of such justices or judges payable from the state treasury; and a sum equal to six and one-half percent of the combined salaries of the justices of the supreme court, the judges of the court of appeals, and the judges of the superior court shall be withdrawn from the general fund of the state treasury. In consideration of the contributions made by the judges and justices to the judges' retirement fund, the state hereby undertakes to guarantee the solvency of said fund and the legislature shall make biennial appropriations from the general fund of amounts sufficient to guarantee the making of retirement payments as herein provided for if the money in the judges' retirement fund shall become insufficient for that purpose, but such biennial appropriation may be conditioned that sums appropriated may not be expended unless the money in the judges' retirement fund shall become insufficient to meet the retirement payments. The deductions and withdrawals herein directed shall be made on or before the tenth day of each month and shall be based on the salaries of the next preceding calendar month. The administrator for the courts shall issue warrants payable to the treasurer to accomplish the deductions and withdrawals herein directed, and shall issue the monthly salary warrants of the judges and justices for the amount of salary payable from the state treasury after such deductions have been made. The treasurer shall cash the warrants made payable to him or her hereunder and place the proceeds thereof in the judges' retirement fund for disbursement as authorized in this chapter.