(40 ILCS 5/16-130) (from Ch. 108 1/2, par. 16-130)
    Sec. 16-130. Creditable service - whole or portion of year.
    (a) Except as provided in paragraph (6) of subsection (b) of Section 16-127, only one year of service is creditable for all service in any one school year.
    (b) For employment prior to July 1, 1990, service rendered for the regular legal school term, if creditable hereunder, is equivalent to one year of service, and time less than a legal school term shall be counted as a portion of a year in the ratio that the number of days paid bears to the number of days required at the time to constitute a legal school term; however, service of 170 or more days in any school year after June 30, 1959 shall constitute a year of service.
    (c) Creditable service for periods of employment after June 30, 1990 shall be calculated as follows:
    For full-time, part-time, and substitute teachers, creditable service in any school year shall be that fraction of a year equal to the ratio of days paid in the legal school term, or the employment agreement if longer, to 170 days.
    (d) Creditable service for optional service verified after July 1, 1990 for periods of employment prior to July 1, 1990 shall be calculated as follows:
    For full-time, part-time, and substitute teachers, creditable service in any school year shall be that fraction of a year that is equal to the ratio of days paid in the legal school term, or employment agreement if longer, to either the number of days required at the time of service to constitute a legal school term or the number of days in the employment agreement, whichever is greater. However, service of 170 or more days in any school year after June 30, 1959 shall constitute a year of service.
(Source: P.A. 86-273; 86-1028; 86-1488.)