Illinois ranks eighth highest in effective individual tax rate at 21.3%, with a median income of $65,318, a state tax rate of 4.7%, and a federal rate of 16.6%. Oregon has the highest total tax rate at 24.4%, followed by Massachusetts at 23.5%. States with no income tax like Florida and Nevada have the lowest tax burdens, around 15.7%. Several states are adopting flat taxes to simplify tax systems.