(40 ILCS 5/15-112) (from Ch. 108 1/2, par. 15-112)
    Sec. 15-112. Final rate of earnings. "Final rate of earnings":
    (a) This subsection (a) applies only to a Tier 1 member.
    For an employee who is paid on an hourly basis or who receives an annual salary in installments during 12 months of each academic year, the average annual earnings during the 48 consecutive calendar month period ending with the last day of final termination of employment or the 4 consecutive academic years of service in which the employee's earnings were the highest, whichever is greater. For any other employee, the average annual earnings during the 4 consecutive academic years of service in which his or her earnings were the highest. For an employee with less than 48 months or 4 consecutive academic years of service, the average earnings during his or her entire period of service. The earnings of an employee with more than 36 months of service under item (a) of Section 15-113.1 prior to the date of becoming a participant are, for such period, considered equal to the average earnings during the last 36 months of such service.
    (b) This subsection (b) applies to a Tier 2 member.
    For an employee who is paid on an hourly basis or who receives an annual salary in installments during 12 months of each academic year, the average annual earnings obtained by dividing by 8 the total earnings of the employee during the 96 consecutive months in which the total earnings were the highest within the last 120 months prior to termination.
    For any other employee, the average annual earnings during the 8 consecutive academic years within the 10 years prior to termination in which the employee's earnings were the highest. For an employee with less than 96 consecutive months or 8 consecutive academic years of service, whichever is necessary, the average earnings during his or her entire period of service.
    (c) For an employee on leave of absence with pay, or on leave of absence without pay who makes contributions during such leave, earnings are assumed to be equal to the basic compensation on the date the leave began.
    (d) For an employee on disability leave, earnings are assumed to be equal to the basic compensation on the date disability occurs or the average earnings during the 24 months immediately preceding the month in which disability occurs, whichever is greater.
    (e) For a Tier 1 member who retires on or after the effective date of this amendatory Act of 1997 with at least 20 years of service as a firefighter or police officer under this Article, the final rate of earnings shall be the annual rate of earnings received by the participant on his or her last day as a firefighter or police officer under this Article, if that is greater than the final rate of earnings as calculated under the other provisions of this Section.
    (f) If a Tier 1 member is an employee for at least 6 months during the academic year in which his or her employment is terminated, the annual final rate of earnings shall be 25% of the sum of (1) the annual basic compensation for that year, and (2) the amount earned during the 36 months immediately preceding that year, if this is greater than the final rate of earnings as calculated under the other provisions of this Section.
    (g) In the determination of the final rate of earnings for an employee, that part of an employee's earnings for any academic year beginning after June 30, 1997, which exceeds the employee's earnings with that employer for the preceding year by more than 20 percent shall be excluded; in the event that an employee has more than one employer this limitation shall be calculated separately for the earnings with each employer. In making such calculation, only the basic compensation of employees shall be considered, without regard to vacation or overtime or to contracts for summer employment.
    (h) The following are not considered as earnings in determining final rate of earnings: (1) severance or separation pay, (2) retirement pay, (3) payment for unused sick leave, and (4) payments from an employer for the period used in determining final rate of earnings for any purpose other than (i) services rendered, (ii) leave of absence or vacation granted during that period, and (iii) vacation of up to 56 work days allowed upon termination of employment; except that, if the benefit has been collectively bargained between the employer and the recognized collective bargaining agent pursuant to the Illinois Educational Labor Relations Act, payment received during a period of up to 2 academic years for unused sick leave may be considered as earnings in accordance with the applicable collective bargaining agreement, subject to the 20% increase limitation of this Section. Any unused sick leave considered as earnings under this Section shall not be taken into account in calculating service credit under Section 15-113.4.
    (i) Intermittent periods of service shall be considered as consecutive in determining final rate of earnings.
(Source: P.A. 98-92, eff. 7-16-13; 99-450, eff. 8-24-15.)