Vesting and benefit eligibility

(1) A member with five years of service credit in one or a combination of more than one of the lifetime benefit components is considered vested for purposes of a pension payable from the lifetime benefit components of the statewide retirement plan. (2) A member is eligible for a normal retirement when: (a) The member has accumulated at least twenty-five years of service credit and has attained age fifty-five; or (b) The member has attained age fifty, the member's combined age and years of accrued service is equal to at least eighty, and the member is not receiving benefits pursuant to part 8 of article 31 of this title 31. (3) A vested member who attains age fifty-five is eligible to terminate service and begin receiving an unreduced benefit. A member who terminates employment before attaining age fifty-five and who has at least five years of service credit may leave contributions in the plan and begin receiving an unreduced benefit upon attaining age fifty-five. (4) An active or inactive vested member who is not eligible for normal retirement, who has attained age fifty, who is not receiving or has terminated benefits pursuant to part 8 of article 31 of this title 31, and who has terminated employment is eligible for an early retirement pension. The early retirement pension for a member is the benefit that the member would have received at age fifty-five reduced on an actuarial equivalent basis to reflect the early receipt of the benefit as determined by the board. (5) Subject to rules adopted by the board, years of service credit of a member who is employed by successive employers may be aggregated for determining eligibility and benefits provided by the lifetime benefit components of the statewide retirement plan if the service for each employer was rendered while the employer covered its members under the statewide retirement plan, the predecessor statewide defined benefit plan, or the defined benefit component of the predecessor statewide hybrid plan.