19-3-1008. Benefit for disability. (1) The monthly amount of the disability retirement benefit payable to a member under the provisions of 19-3-1002(1) is the greater of subsection (1)(a) or (1)(b) as follows:

(a) 90% of one fifty-sixth of the member's highest average compensation multiplied by the member's years of service credit, including any additional service credit purchased under 19-3-513; or

(b) a retirement benefit equal to 25% of the member's highest average compensation.

(2) Except as provided in subsection (3), the monthly amount of retirement benefit payable to a member eligible for disability retirement under the provisions of 19-3-1002(3) is a retirement benefit equal to one fifty-sixth of the member's highest average compensation multiplied by the member's years of service credit, including any additional service credit purchased under 19-3-513.

(3) The monthly amount of retirement benefit payable to a member eligible for disability retirement under the provisions of 19-3-1002(3) who has at least 25 years of membership service is a retirement benefit equal to 2% of the member's highest average compensation multiplied by the member's years of service credit, including any additional service credit purchased under 19-3-513.

(4) The monthly amount of retirement benefit payable to a member eligible for disability retirement under the provisions of 19-3-1002(4) who has:

(a) more than 5 but less than 10 years of membership service is a retirement benefit equal to 1.5% of the member's highest average compensation multiplied by the member's years of service credit, including any additional service credit purchased under 19-3-513;

(b) 10 or more but less than 30 years of membership service is a retirement benefit equal to one fifty-sixth of the member's highest average compensation multiplied by the member's years of service credit, including any additional service credit purchased under 19-3-513; or

(c) 30 or more years of membership service is a retirement benefit equal to 2% of the member's highest average compensation multiplied by the member's years of service credit, including any additional service credit purchased under 19-3-513.

(5) Subject to the provisions of part 11 of this chapter, a retired member receiving a disability retirement benefit on February 24, 1991, who has previously been granted a disability retirement benefit under the provisions of this section will continue to receive the monthly disability retirement benefit as calculated prior to February 24, 1991, subject to any postretirement or cost-of-living increases granted by the legislature.