Number of supporters in the main football nations.

Argentina 
34% Boca Juniors (Buenos Aires)
31% River Plate (-photo-, Buenos Aires)
8% Independiente (Avellaneda)
6% Racing Club (Avellaneda)
6% San Lorenzo (Buenos Aires) 

Brazil
17% Flamengo (Rio)
12% Corínthians (São Paulo)
9% São Paulo 
7% Palmeiras (São Paulo)

Spain
36% Real Madrid 
29% Barcelona 

Italy
24% Juventus 
18% Milan 
17% Inter

England 
18% Manchester United 
17% Liverpool 
12% Arsenal 

Germany
29% Bayern Munich
6% Borussia Dortmund 
6% Schalke 04 

Russia
27% Zenith St. Petersburg 
23% CSKA Moscow
19% Spartak Moscow.

 Source: Sport+Markt.