Recently my husband changed servers for my work email. Within a week I saw my spam cut by more than half. I attributed less junk emails and phishing to this upgrade.
Then I saw this article about a temporary decrease in spam.
Turns out McColo, a company that provides servers for major spammers and scammers was shut down, cutting off as much as 60% of unwanted and deceptive emails.
It has been predicted that spam activity will return to its previous level by Christmas, once the "computer cockroaches" set up shop somewhere else.
So, if you have noticed a substantial decrease in your spam, enjoy it while you can!