(Undated) -- A new report shows Iowa is one of the least tax-friendly states in the country. MoneyGeek says Iowa is one of a dozen states with a tax grade of D or lower. MoneyGeek says the average Iowan pays nearly 14% of their income in taxes. The average tax bill in Iowa is $11,398. MoneyGeek says the most tax-friendly state is Wyoming and the least tax-friendly state is Illinois. The full list of states is available here.