(a) The retirement income for which a member is eligible shall be determined from his retirement date, years of state service and base salary, in accordance with the schedule in subsection (c) or (d) below, whichever is appropriate.

(b) As used in this section: (1) “Base salary” means the average annual regular salary, as defined in subsection (h) of § 5-154, received by a member for his three highest-paid years of state service, disregarding any general temporary reduction or any reduction or nonpayment for illness or other temporary absence; “retirement date” means the date on which a member is retired from state service; “Social Security earnings” means that portion of the member’s base salary up to and including the sum of forty-eight hundred dollars on which the state made contributions under the Social Security Agreement, or would have made contributions had the member been covered under Social Security by the state during the years used in determining his base salary; “excess earnings” means that portion of the member’s annual base salary in excess of his Social Security earnings, provided, if the member has no Social Security earnings because the state has made no Social Security contributions for him, his excess earnings shall equal his base salary. (2) Notwithstanding the provisions of subdivision (1) of this subsection, on and after January 1, 1984, “base salary” means the average covered earnings received by a member for his three highest-paid years of state service, disregarding any general temporary reduction or any reduction or nonpayment for illness or other absence which does not exceed ninety days; and “covered earnings” means the annual salary, as defined in subsection (h) of § 5-154, received by a member in a year, limited by one hundred thirty per cent of the average of the two previous years’ covered earnings. The limit does not apply to earnings for calendar years before 1984 or for the first three full or partial years of employment. The Retirement Commission may adopt regulations in accordance with chapter 54 determining the procedure to be followed for a member who was not employed on a full-time basis for the entire two previous years used to develop such limit.

(c) Schedule 1-Twenty-five or more years of state service.

(1) Except as provided in § 5-163a, each member who has completed twenty-five or more years of state service shall be retired on his own application on the first day of the month named in the application, and on or after the member’s fifty-fifth birthday.

(2) Each member who has completed twenty-five or more years of state service and has reached his seventieth birthday and who is in an appointive position shall continue in service and shall be retired on the first day of the month on or after his seventieth birthday, upon notice from the Retirement Commission to the member, to the executive head of his agency and the Comptroller.

(3) Each member referred to in subdivisions (1) and (2) of this subsection shall receive a monthly retirement income beginning on his retirement date equal to one-twelfth of (A) plus (B): (A) Twenty-five per cent of his Social Security earnings, plus fifty per cent of his excess earnings; (B) the number of years, if any, taken to completed months, of his state service in excess of twenty-five years multiplied by one per cent of his Social Security earnings, plus the number of such years multiplied by two per cent of his excess earnings.

(d) Schedule 2-Less than twenty-five years of state service.

(1) Except as provided in § 5-163a, each member who has completed less than twenty-five years of state service shall be retired on his own application, on the first day of the month following his application, if the member has completed ten years of state service and reached his fifty-fifth birthday.

(2) Each such member in an appointive position who has reached his seventieth birthday shall continue in service and shall be retired on the first day of the month on or after his seventieth birthday, upon notice from the Retirement Commission to the member, the executive head of his agency and the Comptroller.

(3) Each member referred to in subdivisions (1) and (2) of this subsection shall receive a monthly retirement income beginning on his retirement date equal to one-twelfth of (A) plus (B): (A) The number of years of his state service, taken to completed months, multiplied by the applicable percentage of his Social Security earnings determined from the table below for the appropriate age and years of state service; (B) the number of such years multiplied by the applicable percentage of his excess earnings determined from the table below for such age and years of service.

*Not more than 20 years may be counted for this age and percentage group.

**Between the ages of fifty-five and sixty, the minimum service requirement is ten years of actual state service.

For each full year of service beyond ten, the percentage of Social Security earnings shall be increased by one-fifteenth of the difference between one and the percentage shown in the above table opposite the age of the retiring employee, and the percentage of excess earnings shall be increased by one-fifteenth of the difference between two and the percentage shown in the above table opposite the age of the retiring employee.

(e) Each retirement application shall be made to the Retirement Commission and, upon its approval, shall be forwarded to the Comptroller, who shall draw his orders upon the Treasurer for any amounts the applicant is entitled to receive.

(f) Pension contributions made by a member on any earnings excluded from his base salary when calculating the member’s retirement income, pursuant to the maximum limitations on covered earnings in subsection (b) of this section, shall be refunded to the member by the Retirement Commission at the time of his retirement.