On July 1 of each year, for judges who became members on or after July 1, 2015:

(1) The board shall determine the number of retired members or beneficiaries in the retirement system who became members on or after July 1, 2015, and an annual benefit adjustment shall be made by the board for each retired member or beneficiary. The benefit paid to a retired member or beneficiary under this section shall be increased annually by the lesser of (a) the percentage change in the Consumer Price Index for Urban Wage Earners and Clerical Workers for the period between June 30 of the prior year to June 30 of the present year or (b) one percent. If the consumer price index used in this section is discontinued or replaced, a substitute index published by the United States Department of Labor shall be selected by the board which shall be a reasonable representative measurement of the cost-of-living for retired employees;

(2) Each retired member or beneficiary shall receive the sum of the annual benefit adjustment and such retiree's total monthly benefit less withholding, which sum shall be the retired member's or beneficiary's adjusted total monthly benefit. Each retired member or beneficiary shall receive the adjusted total monthly benefit until the expiration of the annuity option selected by the member or until the retired member or beneficiary again qualifies for the annual benefit adjustment, whichever occurs first; and

(3) The annual benefit adjustment pursuant to this section shall not cause a current benefit to be reduced, and a retired member or beneficiary shall never receive less than the adjusted total monthly benefit until the annuity option selected by the member expires.