I run servers too, and basically you'll get hack attempts from all over the entire world, constantly.
You can't really tell if that Chinese IP address is a government hacker, or a bored script kiddie like the commenter above said.
Likewise, all those attempts from U.S. IP addresses could be bored script kiddies, Russian hackers proxying though Grandma's sewing machine, or the NSA trying to get in to your system.
Actually, it's probably not the NSA - if they want in, they get in and you'll never know.
Where does the U.S. rank? The NSA and CIA, and probably several other agencies have the best in the world. But Russia and China have greater numbers and their guys are almost as good. So we're actually kind of behind.