(a) Each Chief State’s Attorney, deputy chief state’s attorney and state’s attorney who elected under the provisions of § 51-278 to be included in the provisions of this section and who has attained the age of sixty-five or who attains the age of sixty-five while serving in office, and each such Chief State’s Attorney, deputy chief state’s attorney and state’s attorney, who has attained the age of sixty and so elects or who so elects on attaining the age of sixty while so serving, shall receive annually as retirement salary, for each year he has served in any such office, one-tenth of two-thirds of the salary of the office which he held at the time of his retirement, as such salary may be changed from time to time; but in no event more than two-thirds of such salary.

(b) Each such attorney shall, for retirement purposes, be entitled to credit for any or all the prior years of service accrued by him on July 1, 1978, while serving in the office of (1) state’s attorney, (2) assistant state’s attorney, (3) public defender in the Superior Court, (4) prosecuting attorney in the Court of Common Pleas, (5) chief prosecuting attorney or deputy chief prosecuting attorney, prosecuting attorney or assistant prosecuting attorney in the Circuit Court, or (6) public defender or assistant public defender in the Circuit Court, provided such attorney shall pay to the Comptroller five per cent of the salary for his office for each prior year of service he claims for retirement credit. Each such attorney shall be entitled to have his retirement contributions to the state employees retirement system under chapter 66 or to the state’s attorneys’ retirement system under this section prior to July 1, 1973, credited toward the payment due for the prior year or years of service he claims for retirement credit hereunder.

(c) If any such attorney resigns or is removed from office before his retirement under this section, he shall be entitled to the return of all contributions made by him under § 51-278, without interest thereon, except that, if the attorney has completed at least ten years of service creditable under this section, he may, at his option, elect instead to receive a retirement income on a reduced actuarial basis, as determined by the Comptroller.

(d) For purposes of determining the retirement salary of each Chief State’s Attorney, deputy chief state’s attorney or state’s attorney under subsection (a) of this section and the allowance payable to their surviving spouses under § 51-288, “salary of the office” shall be composed of the total of the following amounts: The annual salary of the office which he held at the time of his retirement, as such salary may be changed from time to time; and for each Chief State’s Attorney, deputy chief state’s attorney, and state’s attorney to whom a longevity payment has been made or is due and payable, in each instance under § 51-287a, (1) one and one-half per cent of annual salary, as such salary may change from time to time, for those who have completed ten or more but less than fifteen years of service as a Chief State’s Attorney, deputy chief state’s attorney, state’s attorney or assistant state’s attorney, (2) three per cent of annual salary, as such salary may change from time to time, for those who have completed fifteen or more but less than twenty years of service as Chief State’s Attorney, deputy chief state’s attorney, state’s attorney or assistant state’s attorney, (3) four and one-half per cent of annual salary, as such salary may change from time to time, for those who have completed twenty or more but less than twenty-five years of service as a Chief State’s Attorney, deputy chief state’s attorney, state’s attorney or assistant state’s attorney, and (4) six per cent of annual salary, as such salary may change from time to time, for those who have completed twenty-five or more years of service as a Chief State’s Attorney, deputy chief state’s attorney, state’s attorney or assistant state’s attorney.

(e) Any such attorney who is retired under this section and who is appointed a judge shall not receive a retirement salary pursuant to this section during the period such retired attorney serves as a judge.