(i) the Employees’ Retirement System; or

(ii) the Teachers’ Retirement System.

(2) Except as provided in paragraph (3) of this subsection, the average final compensation of a member equals the average annual earnable compensation of the member for:

(i) the 3 years of employment as a member during which the member’s earnable compensation was highest, if the member was employed at least 3 years as a member; or

(ii) the member’s total period of employment, if the member was employed less than 3 years as a member.

(3) Except for a salary increase because of a member’s promotion, the member’s average final compensation does not include a salary increase in the last 3 years of employment if it is an extraordinary salary increase according to regulations that the Board of Trustees adopts.

(b) (1) This subsection applies only to an individual who on or before June 30, 2011, is a member of:

(i) the Correctional Officers’ Retirement System; or

(ii) the State Police Retirement System.

(2) Except as provided in paragraph (3) of this subsection, the average final compensation of a member equals the average annual earnable compensation of the member for:

(i) the 3 years of employment as a member during which the member’s earnable compensation was highest, if the member was employed at least 3 years as a member; or

(ii) the member’s total period of employment, if the member was employed less than 3 years as a member.

(3) (i) Except for a salary increase because of a member’s promotion, the member’s average final compensation does not include a salary increase in the last 3 years of employment if it is an extraordinary salary increase according to regulations that the Board of Trustees adopts.

(ii) 1. This subparagraph applies only to a member of the State Police Retirement System.

2. If a member of the State Police Retirement System who transferred from another actuarial retirement system in the State retires after less than 3 years of employment as a member of the State Police Retirement System, the earnable compensation as a member in the other system shall be used in the determination of average final compensation.

(c) (1) This subsection applies only to an individual who on or after July 1, 2011, becomes a member of:

(i) the Correctional Officers’ Retirement System; or

(ii) the State Police Retirement System.

(2) Except as provided in paragraph (3) of this subsection, the average final compensation of a member equals the average annual earnable compensation of the member for:

(i) the 5 years of employment as a member during which the member’s earnable compensation was highest, if the member was employed at least 5 years as a member; or

(ii) the member’s total period of employment, if the member was employed less than 5 years as a member.

(3) (i) Except for a salary increase because of a member’s promotion, the member’s average final compensation does not include a salary increase in the last 5 years of employment if it is an extraordinary salary increase according to regulations that the Board of Trustees adopts.

(ii) 1. This subparagraph applies only to a member of the State Police Retirement System.

2. If a member of the State Police Retirement System who transferred from another actuarial retirement system in the State retires after less than 5 years of employment as a member of the State Police Retirement System, the earnable compensation as a member in the other system shall be used in the determination of average final compensation.