(

a) The quarterly supplemental payments made from the Supplemental Benefit Maintenance Account pursuant to

Section as of July 1, 2023, shall be increased as follows: Period during which retirement, disability, or death occurred: Percentage increase: After Dec. 31, 1998 0.0% Between Jan. 1, 1990, and Dec. 31, 1998 5.0% Between Jan. 1, 1980, and Dec. 31, 1989 10.0% Prior to Jan. 1, 1980 15.0% (

b) The increase provided by this

section shall be determined on July 1, 2023, by applying the applicable percentage to the sum of the monthly allowance, including all allowance increases authorized by this part, and excluding annuities payable from accumulated annuity deposit contributions and tax-sheltered annuity contributions, and the monthly equivalent of any purchasing power payments made pursuant to

Section 24415. (

c) Two percent of the amount determined pursuant to subdivision (

b) shall be added to the increase provided by subdivision (

a) each year commencing on July 1, 2024. This amount shall not be compounded. (

d) The increases provided pursuant to this

section shall be paid quarterly and are in addition to any payments received by a retired member or nonmember spouse, disabled member, or beneficiary, including an option beneficiary, under

Section 24415. (

e) If the monthly allowance payable is adjusted after the effective date of this section, the percentage increase applied on the effective date of this

section shall be applied to the adjusted monthly allowance payable. (

f) The increases provided by this

section are not part of the base allowance and will be payable only to the extent that funds are available from the Supplemental Benefit Maintenance Account as provided pursuant to

Section 24415. (

g) The increases authorized by this

section are vested only up to the amount payable as a result of the annual appropriation made pursuant to

Section 22954, the application of

Section 24415, and the adjustments made by the board pursuant to

Section 24415.5. (

h) Benefits payable under this

section shall be initially payable by the system on July 1, 2023.