(a) For purposes of this Code section, the term "highest average compensation" means the member's highest average monthly earnable compensation during a period of eight consecutive calendar quarters while a member of the retirement system but shall not include any decrease in salary that is in excess of two 5 percent decreases during such eight calendar quarters.

(b) Any other provisions of this chapter to the contrary notwithstanding, every person who is in service on June 30, 1974, as a conservation ranger of the Department of Natural Resources, or in the Department of Revenue as an alcohol and tobacco officer or agent; every person who enters or reenters such service on or after July 1, 1974; every person who is in service in the Department of Revenue as an officer or agent of the Special Investigations Unit on June 30, 1978; and every person who enters or reenters such service on or after July 1, 1978, shall be deemed a member under this Code section and shall retire upon reaching the mandatory retirement age prescribed by subsection (c) of this Code section; and upon retirement he shall receive the regular retirement benefits under this chapter, provided that in any case he shall receive a monthly retirement benefit equal to at least 2 percent of his highest average compensation for each year of creditable service; provided, further, that he has filed an application therefor in a manner similar to that provided in Code Section 47-2-110.

(c) Any member subject to this Code section shall be retired on the last day of the month following the month in which he reaches 55 years of age, provided that, during the years 1974 through 1979, any such member may be retired on the last day of the month following the month in which he reaches the retirement age set forth below:

Year Retirement_Age

1974.................................................. 60 or over 1975.................................................. 59 1976.................................................. 58 1977.................................................. 57 1978.................................................. 56 1979.................................................. 55

(d) Any member 60 years of age or over on July 1, 1974, shall be retired on July 31, 1974. During the years 1975 through 1979, any member who has reached one of the mandatory retirement ages specified in this Code section by January 1 of a year shall be retired on January 31 of that year.

(e) The Board of Natural Resources may waive the mandatory retirement ages specified in this Code section for conservation rangers as necessary to permit members who entered such service in the department on or before June 30, 1965, to complete service sufficient to provide them with 25 years of total creditable service. Such a member shall be retired on the last day of the month following the month in which he completes such service. The Board of Natural Resources, in its discretion, may waive the mandatory retirement ages specified in this Code section for conservation rangers in a supervisory classification upon application of such members or upon the initiation by the board of trustees, provided that such waivers to members in a supervisory classification shall not be extended to such members who have reached 60 years of age.

(f) Subsections (c) through (e) of this Code section shall not apply to any conservation ranger in a supervisory classification whose supervisory duties are not all or predominantly in the field of law enforcement.

(g) The mandatory retirement ages specified for an alcohol and tobacco officer or agent of the Department of Revenue may be waived by the state revenue commissioner as necessary to permit such members who enter service on or before January 31, 1974, to complete service sufficient to provide them with 25 years of total creditable service. Such a member shall be retired on the last day of the month following the month in which he completes such service. The mandatory retirement ages specified may also be waived by the state revenue commissioner, at his discretion, for alcohol and tobacco officers or agents in a supervisory classification upon application of such officers or agents or upon initiation by the state revenue commissioner, provided that such waivers to members in a supervisory classification shall not be extended to such members who have reached 60 years of age. This subsection shall not apply to any alcohol and tobacco officer or agent in a supervisory classification whose supervisory duties are not all or predominantly in the field of law enforcement.

(h) The mandatory retirement ages may be waived by the state revenue commissioner for an officer or agent of the Special Investigations Unit as necessary to permit such members who entered service on or before January 31, 1974, to complete service sufficient to provide them with 25 years of total creditable service. Such a member shall be retired on the last day of the month following the month in which he completes such service. The mandatory retirement ages may also be waived by the state revenue commissioner, in his discretion, for officers or agents of the Special Investigations Unit in a supervisory classification upon application of such officers or agents or upon initiation by the commissioner, provided that such waivers to members in a supervisory classification shall not be extended to such members who have reached 60 years of age. This subsection shall not apply to any officer or agent of the Special Investigations Unit in a supervisory classification whose supervisory duties are not all or predominantly in the field of law enforcement.