(Undated) -- A new report shows Illinois is the least tax friendly state in the U.S. MoneyGeek says Illinois is one of just three states to get a tax-friendliness grade of E. MoneyGeek says the average Illinois resident pays nearly 17% of their income in taxes. The average tax bill in Illinois is $13,894. Iowa also ranks low for tax-friendliness, getting a D rating. MoneyGeek says the average Iowan pays nearly 14% of their income in taxes. MoneyGeek says the most tax-friendly state is Wyoming. A full list of states is available here.