10 ILCS 5/3-1.3
Whenever this Code or another Statute requires that a nominating petition or a petition proposing a public question shall be signed by a specified percentage of the registered voters of the State, a political subdivision or district or precinct or combination of precincts, the total number of voters to which the percentage is applied shall be the number of voters who are registered in the State, political subdivision or district or precinct or combination of precincts, as the case may be, on the date registration closed before the regular election next preceding the last day on which such petition may be filed in accordance with the general election law. This Section does not apply to the determination of the number of signatures required on a petition filed pursuant to Article IX of The Liquor Control Act of 1934.
10 ILCS 5/3-1.3