1. For a person who retires and who has an effective date of membership on or after July 1, 2015, allowances or benefits must be increased once each year on the first day of the month immediately following the anniversary date the person began receiving the allowance or benefit:
(a) By 2 percent following the 3rd, 4th and 5th anniversaries of the commencement of benefits.
(b) By 2.5 percent following the 6th, 7th and 8th anniversaries of the commencement of benefits.
(c) By the lesser of 3 percent or the increase, if any, in the Consumer Price Index (All Items) published by the United States Department of Labor for the preceding calendar year following the 9th anniversary of the commencement of benefits and each year thereafter.
2. The base from which the increase provided by this section must be calculated is the allowance or benefit in effect on the day before the increase becomes effective.