There is hereby provided, commencing October 1, 1990 to each person whose effective date of retirement for purposes of receiving benefits from the Teachers' Retirement System is prior to October 1, 1989, a cost-of-living increase of $1.00 per month for each year of creditable service attained by said retiree plus $3.00 per month for each year of retirement attained by said retiree.
Ala. Code § 16-25-60 (1975)