Turkish club Galatasaray is the 20th most valuable football team in the world, according to a list released by Forbes on Wednesday that showed the average value of the top 20 teams rose 11 percent over the last year.Although the Turkish club's value fell 15 percent to $294 million, Galatasaray still managed to grab a spot in the top 20 for the second year in a row.The veteran continental contender, ranked 16th last year, now is the world's 20th most valuable football team after a disappointing UEFA Champions League campaign.Meanwhile, Real Madrid has retained its place as the world's most valuable football club despite a 5 percent decrease to $3.26 billion.Barcelona ($3.16 billion), Manchester United ($3.10 billion), German champions Bayern Munich ($2.35 billion) and Manchester City ($1.35 billion) rounded out the top five.Rising television and shirt sponsorship revenue helped drive the average value of the top 20 clubs to $1.16 billion, a staggering 84 percent jump from five years ago.Eight of the top 20 teams are from the English Premier League, which Forbes credited to both a rise in the British pound relative to the euro and U.S. dollar and a lucrative new domestic TV deal starting from the 2016-17 season.Serie A champions Juventus ($837 million), AC Milan ($775 million), Inter Milan ($439 million) and Napoli ($353 million) are the only Italian teams to crack the top 20 but none were higher than ninth place.