Statute Code -> I-UCR Code -> NIBRS UCR Code mapping is available in the "nibrs_CodesTables"spreadsheet, on the "OffenseILUCRCode" tab.
Follow this path to access the spreadsheet.
IL_UCR_SSP\service model\information model

Please note that Statute Codes which map to "Not Reported" NIBRS codes are not to be included in NIBRS submissions.