The article says: "The most recent statistics from the Fed show that as of Dec. 31, there were 10.3 billion $1 bills, in circulation, 8.6 billion $100 bills an

The article says: "The most recent statistics from the Fed show that as of Dec. 31, there were 10.3 billion $1 bills, in circulation, 8.6 billion $100 bills and 7.4 billion $20 bills, followed by $5's, $10's, $50's and $2's. A little more than 75% of the more than $1 trillion of currency in circulation is in $100 bills. Much of it is held outside the United States." If we switched to 20s, we'd need 43 billion more 20s.