The Lincoln Cent was originally introduced in 1909, however the reverse design was changed to an image of the Lincoln Memorial in 1959 to coincide with Abraham Lincoln's 150th birthday. In 1982, the cent underwent a content change due to the rising cost of copper. Except for a thin copper coating, the coin is now predominantly zinc. The Lincoln Memorial design was officially retired in 2009 and a series of four cents were introduced to commemorate the President's 200th birthday. In 2010, the Lincoln Shield Cent was introduced as the Lincoln Memorial Cent's replacement.