Kaspersky Lab recently published an analysis of the state of spam in March 2013, which states that the percentage of spam in e-mail traffic was down by 1 percentage point from the previous month to 70.1 percent, but the percentage of phishing e-mails doubled from the previous month to 0.006 percent.

The researchers also found that malware was found in 4 percent of all e-mails in March 2013, an increase of 1.2 percent from February.

According to Kaspersky, the death of Venezuelan president Hugo Chavez in March led to a notable surge in so-called "Nigerian letters."

"One of the fraudulent emails was sent on behalf of a Venezuelan seaport chief who allegedly asked for help in collecting the money he had got from the sale of diesel fuel to Southern Sudan," the researchers write. "In their first email the scammers did not offer the victim any specified sum of money for his help, their goal at the initial stage was to provoke the recipient’s interest and make him respond to the email. In further correspondence the victim was offered a reward."

Fully 25.8 percent of all spam in March was sent from China, with the US in second place at 17.3 percent. South Korea came third at 9.8 percent, with Taiwan in fourth place at 5 percent.

"In April, we expect to see an overall reduction in the amount of holiday spam, although there is likely to be a round of Russian-language Easter spam," the researchers write.

The full report is available here.