40 ILCS 5/7-151

Permanent disability benefits shall be payable: (a) As of the date temporary disability benefits are exhausted; (b) Once a month as of the end of each month; (c) For less than a month in a fraction equal to that created by making the number of days of disability in the month the numerator and the number of the days in the month the denominator; (d) To the beneficiary of a deceased employee for the unpaid amount accrued to the date of death; (e) While total and permanent disability continues; (f) For the period ending on the last day of the month which is the later of the following: 1. the month that the participating employee attains the age for a full Social Security old-age insurance benefit; 2. the month which is 5 years after the month the participating employee became disabled as provided in Section 7-146.