Ha! I love this. Some young economist named Patrick DeJarnette looked into what combination of coins would be more efficient than our current 1, 5, 10, 25 setup. As he explains, “What’s a little surprising is how inefficient our current setup is! It’s only the 2,952-nd most efficient combination. There are effectively 152,096 different combinations of penny + three coins. In other words, it’s only in the 98th percentile for efficiency.”
As the Stephen Levitt, the Freakonomics blogger observes, what might be funniest about that is that, “he [Patrick DeJarnette] finds that the current government solution for the coins we use is 98 percent efficient and thinks this is inefficient.”
Anyway, he also figures out the most efficient combination of coins: 1, 3, 11 and 37 which would officially make the US the most obnoxious place in the world (the combo leads to 4.1 coins per transaction). In the realm of reasonable coin amounts, 1, 5, 15 and 35 wins out at 4.5 coins, which is not too bad (and 1, 5, 10 and 30 is only slightly worse at 4.6). Anyway, here’s to the three-cent piece.