The Walker Cup is a golf trophy contested biennially in odd numbered years between teams comprising the leading amateur golfers of the United States and Great Britain and Ireland. The event, officially called the Walker Cup Match (not "Matches", unlike the professional Ryder Cup Matches), is co-organised by the R&A and the United States Golf Association, and is named in honor of George Herbert Walker (grandfather and namesake of the George H. W. Bush, 41st President of the United States and great-grandfather of George W. Bush, 43rd President of the United States), who was president of the USGA in 1920 when the series was initiated. There was an unofficial event in 1921 at Royal Liverpool and annual events to 1924. From that time on it became a biennial event, and after World War Two it switched to odd numbered years. It is played alternately on either side of the Atlantic. Unlike the Ryder Cup, which also began as a competition between the U.S. and the United Kingdom, the Walker Cup has never been expanded to make all European amateur golfers eligible to compete. There is little present competitive reason to do so: although the United States leads the series 34 to 8, with one halved match, through 2011, the two teams have been far more evenly matched in recent decades. Starting with the 1989 Match in which Team GB&I ended Team USA's eight-match winning streak, both teams are tied at 6–6. The 1989 Match and the three matches between 2003 and 2007 were all decided by one point. — at National Golf Links Of America.