Ron Guth: In 1857, the U.S. Mint produced two different Cents: the old-style Large Cent and a new, smaller cent with an eagle flying left across the obverse. One of the motivating factors for the creation of the new "Small" Cent was the high price of copper. Each new Small Cent required less than half the amount of copper than the Large Cent, yielding significant savings for the U.S. Treasury.
To introduce the new design, the Mint produced a then-record high 17,450,000 Flying Eagle Cents, making it the first Cent with a mintage over 10 million coins. Because of public and collector interest, large quantities were saved, making it very easy to find an example today. Mint State examples are quite common and are usually seen in MS-64 (and to a lesser degree in MS-63). Gems are only slightly scarce, but in MS-66 the population drops precipitously. As of July 2011, none have been graded finer then MS-66 by PCGS.