The U.S. relayed more spam than any other nation, accounting for a massive 28.4 percent. Almost one in three of all the world’s spam emails is being sent through a compromised US. computer. Second placed South Korea only responsible for relaying 5.2 percent, or one in 20 spam messages. The top 12 spam-relaying countries are as follows: The United States, South Korea, China (inc. Hong Kong) Russia, Brazil, France, Germany, Turkey and Poland.”]
Source: https://www.darkreading.com/attacks-breaches/us-still-no-1-spam-relayer