97% of email is spam

The majority of these spam messages are advertising drugs. A lot of them come with malicious attachments, like viruses and malware. A global study from Microsoft found that for every 1,000 computers in the world, 8.6 were infected. The countries most affected were Russia, Brazil, Serbia and Montenegro, and Turkey.

Microsoft also found that 91% of the malware sent on spam emails were already obsolete. Attacks from these malicious email attachments were already preventable by using 2-year-old software updates.
(source)