(35 ILCS 200/9-205)
When deemed necessary to equalize assessments
between or within townships or between classes of property, or when deemed
necessary to raise or lower assessments within a county or any part thereof to
the level prescribed by law, changes in individual assessments may be made by a
township assessor or chief county assessment officer, under Section 9-75, by
application of a percentage increase or decrease to each assessment.
(Source: P.A. 81-1034; 88-455.)