20 visiting now: 8 USA 
3 China 
2 India 
2 Germany 
2 Russia 
1 Brazil 
1 Pakistan 
1 Ghana 
3 China 2 India 2 Germany 2 Russia 1 Brazil 1 Pakistan 1 Ghana 3 China 2 India 2 Germany 2 Russia 1 Brazil 1 Pakistan 1 Ghana