65 ILCS 5/11-98-3
Any specified municipality which heretofore has authorized or hereafter may authorize the levy of the tax provided for by Section 11-98-1 or by "An Act to authorize certain cities and villages to establish and maintain public parks by taxation and to lease the same to county fairs," approved May 13, 1907, as amended, at a time when the population of the municipality was less than 50,000, may continue the levy annually at one-half of the rate approved by the referendum required under Section 2 of that Act or at the rate provided under Section 11-98-1, notwithstanding that after that approval the population of the municipality has increased to 50,000 or more.
The foregoing limitations upon tax rates may be increased or decreased according to the referendum provisions of the General Revenue Law of Illinois.
65 ILCS 5/11-98-3