The U.S. Treasury has called a halt to the automatic production of large numbers of $1 coins bearing the image of former presidents, saying that the savings will be $50 million a year.

A 2005 law instructed the U.S. Mint to issue four new coins every year, each with a different former president on the face, from 2007 to 2016. The number of coins required was quite high: 70-80 million per president.

The Treasury has had varied success in selling these coins. Nearly $1.4 billion worth of the coins, 40 percent of what was produced, lie unsold in federal vaults, after being returned because of lack of demand.

So far, 20 of the 39 former presidents have been honored with a commemorative coin, in the order in which they served. Those appearing on coins in 2011 were Andrew Johnson, Ulysses S. Grant, Rutherford B. Hayes, and James A. Garfield.

The coins will still be released, continuing with Chester A. Arthur in spring 2012; but the number produced will be much lower and collectors, the main buyers of the coins, will be required to pay for more of the cost.