Borussia Dortmund dominate the world rankings of clubs with the highest average attendance between 2013 and 2018. According to CIES Football Observatory, the German team really excels on this front with an average of 80230 fans, ahead of Manchester United, Barcelona, Bayern Munich and Real Madrid. To close out the top 10 is MLS team Atlanta United (founded only in 2017), averaging 51 thousand fans.
The first Italian club is Inter (23rd overall) with 46654, just behind Atletico Madrid and ahead of Feyenoord and PSG. Milan are behind its cousins (32nd in the standings) with 41495, surpassed also by Club America and Seattle Sounders but the Rossoneri are ahead of Chelsea.
Juventus are 42nd at 38778 fans per match, lower than Athletico Bilbao Tigres UANL, Monterrey and Sunderland.
Source: CIES Football Observatory