25 visiting now: 17 USA 
4 UK 
3 Singapore 
2 China 
1 Germany 
1 Iran 
1 Taiwan 
1 Canada 
4 UK 3 Singapore 2 China 1 Germany 1 Iran 1 Taiwan 1 Canada 4 UK 3 Singapore 2 China 1 Germany 1 Iran 1 Taiwan 1 Canada