Only Mississippi, S. Carolina, Idaho and Arkansas have lower federal tax burdens than Hawaii, according to new research.

Arkansas residents have the lowest federal tax burden in the U.S., the study by personal finance site MoneyRates.com found.

Residents of Washington D.C. have a higher federal tax burden than people who live in all 50 states.

The analysis measured two main factors: the amount a state (or Wash., D.C.) pays in federal income taxes per capita, and an equally weighted calculation of effective federal income tax rates across income brackets.

The weighting was intended to avoid skewing the state’s average tax rate in accordance with its relative wealth, the announcement of the study said.

The No. 2 federal tax burden is in Massachusetts, followed by Connecticut at No. 3, N. Dakota at No. 4, with Alaska and New Jersey tied for fifth-highest.

The rest of the top 10 most-burdened states are New York (7), Illinois and Texas (tied at No. 8), and No. 10, Pennsylvania.

The study did not take state or local taxes into account.