Appeal from the Circuit Court of Kane County. No. 03-MR-209 Honorable Michael J. Colwell, Judge, Presiding.
 The opinion of the court was delivered by: Justice McLAREN
 Plaintiffs, the Board of Education of Batavia (Board), Unit School District No. 101, Kane County, State of Illinois (District), and Barbara Douglas, appeal the trial court's order granting summary judgment in favor of defendants, John A. Cunningham, as the clerk of the County of Kane, Illinois (Clerk), and David J. Rickert, as the treasurer of the County of Kane, State of Illinois, in this tax levy case. We affirm.
 Before a recitation of the facts of this case, we find it necessary to give a brief overview of the taxing structure applicable to this case. The school district's property tax is made up of several individual taxes. We will refer to the rates for these taxes as individual fund rates. The referendum at issue in this case sought to increase the tax rate for the educational purposes tax, which is an individual tax. There is also a maximum aggregate rate, which limits the total tax rate that the school district can levy. Therefore, the aggregate of the individual fund rates cannot exceed the maximum aggregate rate. If an individual fund rate is increased by referendum, there is also an impact on the aggregate maximum rate. The calculations used to adjust the maximum aggregate rate based on the increase of an individual fund rate are what is at issue in this case. With this background in mind, we recite the facts of this case.
 On April 1, 2003, the voters of Batavia Unit School District No. 101, Kane County, Illinois, passed a referendum authorizing a tax rate increase in the District's educational fund. The ballot question presented to the voters read as follows:
"Shall the maximum annual tax rate for the educational
purposes of Batavia Community Unit School District Number 101, Kane
County, Illinois, be increased and established at 3.34 percent upon
all the taxable property of said District at the value, as
equalized or assessed by the Department of Revenue, instead of 3.18
percent, the existing maximum rate otherwise applicable to the next
taxes to be extended for said purposes?
a) The approximate amount of taxes extendible for educational
purposes under the proposed rate is $25,143,520, and the
approximate amount of taxes extendible for Educational purposes
under the existing maximum rate is $23,939,040, representing an
increase of 5.03 percent.
b) The percentage of increase between the maximum rate at
which the Education tax may be levied if the proposition is
approved and the annual rate at which such tax is currently levied
is 19.85 percent.
c) The total dollar amount of most recently approved annual
budget of said District is $49,038,561. If increased by the amount
of additional tax which may be levied if said proposition is
approved, the total dollar amount of this budget will be
$53,202,298, representing an increase in the total dollar amount of
this budget of 8.49 percent." (Emphases added.)
 After the referendum passed, the Board passed a supplemental budget and a supplemental levy pursuant to section 17--3.2 of the School Code (105 ILCS 5/17--3.2 (West 2002)). The Clerk extended the levy. Part of the calculation required to extend the levy is contained in section 18--230 of the Property Tax Extension Limitation Law (Tax Limitation Law) (35 ILCS 200/18--230 (West 2002)). The section 18--230 calculation requires use of the "rate increase approved." The rate increase approved was 0.16%, which was determined by calculating the difference between the old maximum educational fund tax rate (3.18%) and the newly approved maximum educational fund tax rate (3.34%). The Clerk extended the taxes for the District to the extent allegedly allowed within the limitations contained in the Tax Limitation Law (35 ILCS 200/18--185 et seq. (West 2002)).
 On May 1, 2002, plaintiffs filed a complaint for declaratory judgment and mandamus against defendants, claiming that the "rate increase approved" by the referendum for purposes of the section 18--230 calculation was higher than the "rate increase approved" calculated by the Clerk. Plaintiffs claimed that, rather than the 0.16 extended, the increase should have been 0.5531, which was the difference between the last rate actually extended for the District's educational fund (2.7869%) and the new maximum rate provided in the referendum (3.34%). Plaintiffs argued that the Clerk's erroneous calculation resulted in a loss of millions of dollars of revenue to the District and its constituents.
 The parties filed motions for summary judgment. After hearing arguments, the trial court granted defendants' motion for summary judgment and denied plaintiffs' motion for summary judgment. The trial court stated that the Clerk correctly calculated the increase at 0.16, extended the school district's tax levies, and applied the provisions of the Tax Limitation Law (35 ILCS 200/18--185 et seq. (West 2002)). This timely appeal followed.
 On appeal, plaintiffs argue that the trial court erred by granting defendants' motion for summary judgment because the rate increase approved should have been measured from the current effective rate of 2.7869% rather than from the existing maximum rate of 3.18%, which would have resulted in an increase of 0.5531 rather than an increase of 0.16%. Plaintiffs argue that the Clerk erroneously applied the limits provided in the Tax Limitation Law. Defendants argue that the referendum approved an increase of the District's levy authority under section 18--230 of the Tax Limitation Law (35 ILCS 200/18--230 (West 2002)), but not beyond the limitations provided in section 18--205 of the Tax Limitation Law (35 ILCS 200/18--205 (West 2002)). Thus, according to defendants, the Clerk properly increased ...