23 visiting now: 16 USA 
3 Russia 
2 Germany 
2 China 
1 Colombia 
1 Hong Kong 
1 Argentina 
1 Brazil 
3 Russia 2 Germany 2 China 1 Colombia 1 Hong Kong 1 Argentina 1 Brazil 3 Russia 2 Germany 2 China 1 Colombia 1 Hong Kong 1 Argentina 1 Brazil