The Australian Zone Nationals has been held annually since 1999. The main event is the team competition, which currently attracts approximately 20 teams of between 5 and 6 players (plus alternates) from every Australian state and territory. Teams play about 24 games before semi-finals. All games have three teams playing. Typically all teams get a go in semifinals, but the system is stacked to favour teams who finished higher on the ladder at the end of the preliminary rounds. The scheme used is typically an Ascension or Skip Ascension. In 2007 the decision was made to switch final systems to System D. The top three teams go into a grand final, which is a three-game series in which each team plays on each colour once.