John Roberts is a citizen of Ireland who has resided in Boca Raton for the last four years. John works for an international corporation and is paid $100,000 in 2014. As part of his annual employment summary, his company states that 100 of his working days were in London, and 265 in the U.S. Assuming John would fall in the 25% tax bracket, what is his tax liability for this income in 2014?