Amazingly little. Not even spendable any more since the new Pound coin is out. They demonetized the round ones, I'm pretty sure. The estimate by the Brits was that about 1/3 of "round pounds" in circulation were fakes, thanks to those fine people in the PRC and Russia. This is the same PRC that sent back more "damaged" Kennedy halves to the Mint for replacement than were MADE by the U.S. Mint. Funny thing, math.
