The U.S. is closely followed by China, with 22.3 percent. South Korea rounds out the top three with 9.7 percent, according to Sophos, which said the level of non-English language spam is rising. The company bases its numbers on a scan of all junk mail caught by its spam traps.
While the U.S. still tops the chart, the latest figures mark the first time the country accounts for less than one quarter of all spam relayed, Sophos said. The decrease is a continuing trend. Last October, 26.3 percent of all spam sent from April through September last year was, a significant drop from 41.5 percent a year earlier, Sophos said.
The decline in U.S.-sourced spam is thanks in part to the crackdown against fraudulent e-mail, Sophos said. In particular, the company pointed to monetary damages that spammers have been ordered to pay as well as, and .
The numbers do suggest, however, thattwo years ago that the has not come true.
The spam tide appeared to slow in the first half of last year, with an annual average of 68.6 percent of all e-mail identified as spam, according to recent MessageLabs data. However, in the closing months of 2005, the rate of spam e-mail increased, and in the most frequently targeted industry sectors, telecommunications and health care, eight out of 10 messages was spam, according to MessageLabs, which sells a spam-blocking service.
The majority of the junk mail, 60 percent, is now being relayed by, that are at the beck and call of cybercriminals, Sophos said.
A zombie is typically infected by a Trojan horse or other malicious code and is used remotely to send spam, mount denial-of-service attacks, or other online crimes. The criminals typically rent out the capabilities of their network of zombies, also called a botnet.
Jumps in the number of spam messages can also be attributed to "pump-and-dump" schemes that advertise stock, Sophos said.
The top 12 spam relaying countries, according to Sophos, are as follows:
1. United States, 24.5 percent
2. China, 22.3 percent
3. South Korea, 9.7 percent
4. France, 5 percent
5. Canada, 3 percent
6. Brazil, 2.6 percent
7. Spain, 2.5 percent
8. Austria, 2.4 percent
9. Taiwan, 2.1 percent
10. Poland, 2 percent
10. Japan, 2 percent
12. Germany, 1.8 percent