50 ILCS 20/16.1
The total amount of outstanding bonds issued by any Public Building Commission of any municipality or county with a population of less than 1,000,000 inhabitants shall not exceed 5% of the total assessed value of taxable property in the municipality or the county as the case may be, except as authorized by a referendum held in the municipality or the county as the case may be.
(from Ch. 85, par. 1046.1)
(Source: P.A. 80-749.)