The UEFA Champions League, known until 1992 as the European Champion Clubs' Cup or colloquially as the European Cup, is an annual association football cup competition organised by UEFA since 1955. Originally a straight knockout competition open only to champion clubs, the tournament was expanded during the 1990s to incorporate a round-robin group phase and more teams. The expansion resulted in more games being played, increasing players' goalscoring chances; thus the rankings are weighted in favour of modern players: only six out of the 50 players on the list never competed in the reformed Champions League.