The number used by Wayne Gretzky when he played in the NHL (and WHA). It is now a retired number league-wide, and cannot be used by any players in the future. It is thought, however, if one of his children makes it to the NHL that the league will allow him (or her) to use the number.
Other players have tried wearing 99 during the same time period as Wayne Gretzky (Wilf Paiement being one of them) but have quickly changed to another number because of it's association to Gretzky.
Because of Wayne Gretzky's international fame and popularity, most fans of the sport of hockey will immediately be able to identify the wearer of 99, or tell you what number Wayne Gretzky wore throughout his career.
Wayne Gretzky (according to stories) chose the number 99 as a tribute to his favourite hockey player, Gordie Howe, who wore number 9. Since Gretzky's adoption of the double digit number, many other NHL players have adopted double digit numbers when joining the league (or switching teams/numbers): Mario Lemieux (66), Eric Lindros (88), Paul Coffey (77), Rob Brown (44), Larry Murphy (55). | 
