Following Aston Villa's relegation to the Championship at the end of the season, just six teams have competed in every Premier League season. These are Arsenal, Chelsea, Liverpool, Manchester United, Tottenham Hotspur and West Ham United. The current Premier League season is the 20th to finish since it began in 1992. This article will only cover the first 19 seasons of the league; for the most recent one, see here: 2018-19 Premier League season. The number of teams participating in each season has varied from 26 to 32, depending on how many top-division places were available due to league restructuring or disqualifications. The total number of games played across all seasons is approximately 3604 (based on information provided by the Premier League). Clubs in the Premier League are allowed to replace one player with a new one if his contract expires, but they cannot change formation or style of play. If a club violates this rule, then their record would be expunged from the table with no further action taken against them.