35 ILCS 200/18-40
Each county clerk shall apply the percentages certified by the Department and enter the equalized valuations in the columns provided for that purpose. The percentages certified by the Department shall be applied to the assessed valuation of property, as corrected and equalized by the board of review, board of appeals, or local assessment officers. In all cases of extension of valuations where the equalized valuations are fractional, the clerk shall reject all fractions that fall below 50. Fractions of 50 or more shall be extended as $1.
If the equalized assessed value of any property is less than $150 for an assessment year, the county clerk may declare the imposition and collection of all tax for that year to be extended on the parcel to be unfeasible and cancelled. No tax shall be extended or collected on the parcel for that year and the parcel shall not be sold for delinquent taxes.
35 ILCS 200/18-40