65 ILCS 5/8-2-9.3
The municipal budget officer shall compile a budget, such budget to contain estimates of revenues available to the municipality for the fiscal year for which the budget is drafted, together with recommended expenditures for the municipality and all of the municipality's departments, commissions, and boards. Revenue estimates and expenditure recommendations shall be presented in a manner which is in conformity with good fiscal management practices. Substantial conformity to a chart of accounts, now or in the future, recommended by the National Committee on Governmental Accounting, or the Auditor of Public Accounts of the State of Illinois, or the Division of Local Governmental Affairs and Property Taxes of the Department of Revenue of the State of Illinois or successor agencies shall be deemed proof of such conformity. The budget shall contain actual or estimated revenues and expenditures for the two years immediately preceding the fiscal year for which the budget is prepared. So far as is possible, the fiscal data for such two preceding fiscal years shall be itemized in a manner which is in conformity with the chart of accounts approved above. Each budget shall show the specific fund from which each anticipated expenditure shall be made.
65 ILCS 5/8-2-9.3