The United States continues to be the main source of spam, relaying more than 13 percent of global spam, according to a new report from Sophos.

China has had a significant drop in the amount of spam originating from that country, falling out of the top twelve and coming in at 15th place for relaying just 1.9 percent of the world’s spam.

The top twelve spam relaying countries for January to March 2010

"All eyes aren’t so much on which countries are on the list, but the one which isn’t. China has earned itself a bad reputation in many countries’ eyes for being the launch pad of targeted attacks against foreign companies and government networks, but at least in the last 12 months they have demonstrated that the proportion of spam relayed by their computers has steadily declined," said Graham Cluley, senior technology consultant at Sophos.

"South Korea, Brazil, India and the United States account for more than 30% of all the spam relayed by hacked computers around the globe."

Spam accounts for a 97% of all email received by business email servers, putting both a strain on resources and accounting for a huge amount of time to lost productivity.