An additional $1,000 to your exemption is appropriate if you or your spouse are 65 or older - see the following excerpt from the IL Department of Revenue
"If you (or your spouse if married filing jointly) were 65 or older and/or legally blind, the exemption allowance is an additional $1000, whichever is applicable. Please see the IL-1040 instructions for additional information."
http://www.revenue.state.il.us/QuestionsAndAnswers/851.htm
