I setup a server in Japan and recorded every IP connection over a 30 day period. This is every IP address which made any connection to any port. I recorded 2.6 million unique IPv4 addresses connecting from 186 countries. The top 10 countries by connection:
Connections Country of Origin
111,722 United Kingdom
599,934 United States
674,144 Russian Federation
The server was not advertised anywhere. It just sat there idle recording all the connections (tcp, udp, icmp) of any type, even a single packet to my host.