Spam volume has now climbed to 230 billion messages per day, up from 200 billion at the start of 2010. Spam continues to grow largely due to the growth in malicious botnets. M86 Security has created the “Top Ten Most Wanted” Spam-Spewing Botnets list. Many of them are believed to be controlled in Eastern Europe by criminals who manipulate compromised systems, mostly PCs, around the world to generate spam, according to security firm Sophos. Other “Other” spambots account for 10.7% of all spam.”]
Source: https://www.csoonline.com/article/2125412/the-top-10–most-wanted–spam-spewing-botnets.html