Does anyone know what country is the main victim?
Sure, according to Symantec's 2018 Internet Security Threat Report it's the U.S.
But what's the reason for it?
The U.S. ranks so high, because of laws that require reporting of data breaches. A lot of data breaches aren't reported in other countries, because they don't legally have to.
It sounds unusual. I've never heard about it before.