Every day we throw our pocket change into a little box by the door, and once every six months or so, we sit down and roll it into bank coin wrappers while watching television. Sure, we could just take it to one of the coin-sorting machines at the local Commerce Bank, but rolling coins is relaxing and it only takes about an hour to roll a couple of hundred bucks worth of coins. Anyway, the other night we were doing this, and noticed something strange: we had 360 quarters, 200 dimes, 80 nickels and 300 pennies. Quarters, dimes, and nickels seemed really overrepresented-- and pennies were strangely scarce!

Curious, we tried to go online and find out the percentages of each coin in circulation in America, but it turned out to be surprisingly hard to track down the data. For $5, we put in a Google Answers request, and several helpful people tracked down the production figures for the US Mint. Of course, that only told us the ratios for what the mint produced over the last fifteen years or so-- not what's actually in circulation right now.

The chart above shows the percentages of various coins produced by the United States from 1990 to 2000. Indeed, it does look like our coin collection was unusual: in a typical jar of 940 coins, you'd expect 625 pennies, 77 nickels, 124 dimes, and 112 quarters. So we definitely have too many quarters, dimes, and nickels, and not enough pennies. So the question is: where did all those pennies go?