A Kaspersky Lab research report for November 2010 showed the amount of email based spam fell 0.06 percent to 76.8 percent from October. The study also showed there was a.47 percent decrease in the prevalence of phishing emails across all mail traffic. The decrease in spam may seem small, but this is because October and September saw such dramatic decreases in spam resulting from the shutdown of Pushdo/Cutail and Bredolab botnets, the SpamIt partner program announcing its closure, and the arrest of Spamit leader Igor Gusev.
Source: https://threatpost.com/reports-show-prevalence-spam-dropping-123010/74812/