The program began on January 1, 2007, and like the 50 State Quarters program, was not scheduled to end until every eligible subject was honored. The program was to issue coins featuring each of four presidents per year on the obverse, issuing one for three months before moving on to the next president in chronological order by term in office. To be eligible, a President must have been deceased for at least two years prior to the time of minting. The U.S. Mint called it the Presidential $1 Coin Program. The reverse of the coins bears the Statue of Liberty , the inscription "$1" and the inscription "United States of America". Inscribed along the edge of the coin is the year of minting or issuance of the coin, the mint mark, 13 stars, and also the legend E Pluribus Unum in the following arrangement: ?????????? 2009 P or D ??? E PLURIBUS UNUM ; before 2009, In God We Trust was also part of the edge lettering. The legend " Liberty " is absent from the coin altogether, since the decision was made that the image of the Statue of Liberty on the reverse of the coin was sufficient to convey the message of liberty. The text of the act does not specify the color of the coins, but per the U.S. Mint "the specifications will be identical to those used for the current Golden dollar". The George Washington $1 coin was first available to the public on February 15, 2007, in honor of Presidents' Day , which was observed on February 19. This marked the first time since the St. Gaudens Double Eagle (1907–33) that the United States had issued a coin with edge lettering for circulation. Edge-lettered coins date back to the 1790s. The process was started to discourage the shaving of gold coin edges, a practice which was used to cheat payees. In December 2007, Congress passed H.R. 2764 , moving "In God We Trust" to either the obverse or reverse of the coins. The act had been introduced because of the failure of the Sacagawea $1 coin to gain widespread circulation in the United States. The act sympathized with the need of the nation's private sector for a $1 coin, and expected that the appeal of changing the design would increase the public demand for new coins (as the public generally responded well to the State Quarter program). The program was also intended to help educate the public about the nation's presidents and their history. In the event that the coins did not catch on with the general public, the Mint hoped that collectors would be as interested in the dollars as they were with the State Quarters, which generated about $4.6 billion in seigniorage ( i.e., the difference between the face value of the coins and the cost to produce them) between January 1999 and April 2005, according to a report by the Congressional Budget Office . Stack showing writing on edge Unlike the State Quarter program and the Westward Journey nickel series , which suspended the issuance of the current design during those programs, the act directed the Mint to continue to issue Sacagawea dollar coins during the presidential series. The law states that at least one in three issued dollars must be a Sacagawea dollar. Furthermore, the Sacagawea design is required to continue after the Presidential Coin program ends. These requirements were added at the behest of the North Dakota congressional delegation to ensure that Sacagawea, whom North Dakotans consider to be one of their own, ultimately remains on the dollar coin. However, Federal Reserve officials indicated to Congress that "if the Presidential $1 Coin Program does not stimulate substantial transactional demand for dollar coins, the requirement that the Mint nonetheless produce Sacagawea dollars would result in costs to the taxpayer without any offsetting benefits." In that event, the Federal Reserve indicated that it would "strongly recommend that Congress reassess the one-third requirement." The one-third requirement was later changed to one-fifth by the Native American $1 Coin Act , passed on September 20, 2007. Previous versions of the act called for removing from circulation dollar coins issued before the Sacagawea dollar, most notably the Susan B. Anthony dollar , but the version of the act which became law merely directs the Secretary of the Treasury to study the matter and report back to Congress. The act required federal government agencies (including the United States Postal Service ), businesses operating on federal property, and federally funded transit systems to accept and dispense dollar coins by January 2008, and to post signs indicating that they do so.