Data source for average effective personal income tax rate? Anyone know a source for the average effective personal income tax rate for the US. By state also would be great.

Definition: average effective income tax rate = (Total income tax collected)/(Total income earned)

Possibly a source for the data to do the calculation.
For a lot of things, including average effective (Federal) tax rates, the Urban Institute/Brookings Institution Tax Policy Center is a great place to start. Look at the table that reads "Average Individual Income Tax Rate," as the first one also includes payroll, excise, and corporate taxes.