Economist Kenneth Rogoff had a more practical idea, but one that might be almost as unpopulargetting rid of paper currency altogether. Most money and payments are just ones-and-zeroes stored on a server already. The bills and coins in your pocket are an interest-free loan to the government that produced them anyway. With actual interest rates around zero for much of the past 16 years, demand boomed, especially outside the U.S., for $100 bills, the easiest denomination to store but the hardest one to spend. There are now more of them in existence than ubiquitous $1 bills