(a) As used in this Code section, the term "beneficiary" shall have the meaning specified in paragraph (7) of Code Section 47-3-1.

(b) Subject to the limitations of subsection (c) of this Code section, effective July 1, 2006, the monthly retirement benefit of each beneficiary shall be increased by a percentage which varies in accordance with the time of retirement as follows:

Time of Retirement Percentage Increase

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Prior to July 1, 1974 10.0

July 1, 1974, through June 30, 1982 6.0

July 1, 1982, through June 30, 1987 2.0

After June 30, 1987 0.0

(c) The full percentage increase provided for in subsection (b) of this Code section shall apply only to those beneficiaries who had 20 or more years of creditable service at the time of retirement. For those beneficiaries who had at least ten but less than 20 years of creditable service at the time of retirement, the monthly benefit increase provided for by subsection (b) of this Code section shall be reduced by 5 percent for each year less than 20 years of creditable service. Beneficiaries who had less than ten years of creditable service shall not receive an increase in their monthly retirement benefit under this Code section.

(d) Any county, municipal, or local board of education is authorized, but not required, to provide a postretirement benefit increase as provided in this Code section to any teacher who retired under a public retirement system or fund maintained by such county, municipal, or local board of education, provided that:

(1) The actuary for the fund certifies that such increase would not result in any unfunded accrued liability as to such retirement system; or

(2) The affected political subdivision appropriates sufficient funds to cover the actuarial cost of granting such benefit.