1999 Topps is a 462-card set released in two series of 242 and 220 cards. To commemorate Mark McGwire's 1998 season, card #220 was issued in 70 different variations (one for each home run) to honor his record setting season. Cumulatively, the production of #220 is equal to any other base set card; individually, each card was produced in 1/70th the supply of the other base cards. In Series Two, a similar card of Sammy Sosa (#461) was issued in 66 different varieties. A base sets is considered complete with any one of the 70 McGwire and 66 Sosa variations.