The volume of e-mail made up of spam has stabilized, according to figures from Symantec's Brightmail unit.

December's figures, culled from traffic travelling through its servers, showed that 67 percent of e-mail is now spam, identical to the previous month. That was after three months when spam volumes were stable at 66 percent.

This is still equivalent to tens of millions of messages per day, but the statistics will come as welcome relief after recent dire predictions that the phenomenon would soon account for nearly all email sent.

According to the company's figures, the volume of spam e-mail crossed the 50 percent barrier as long ago as July 2003.

Scams and fraud now account for 24 percent of the spam sent, making it the fastest growing type of spam. Other prominent categories include product advertising (23 percent), health remedies (11 percent), and pornography (14 percent).

The new figures are broadly consistent with those from rival spam antispam vendor MessageLabs, which released figures in for November 2004 showing a spam volume rate of almost 74 percent.

The two companies aren't entirely in step however. The MessageLabs figures for last July claimed spam had consumed 94 percent of all e-mail sent, so the more recent figure was actually a significant fall. The company suggested that past dips in spam volume have corresponded to legal measures enacted around the globe to curb its rise.

Tumbleweed Communications, which analyses traffic travelling through its managed service hubs, agreed the volume of spam reaching ISPs might have decreased. By contrast, the company said it had seen an increase in spam targeting large enterprises.

"As more ISP introduce spam filtering, spammers are looking for new ways to get through to people, and that means spam is moving from ISPs to corporate email networks," said David Brunswick, Tumbleweed's EMEA technical director.

Symantec Brightmail's statistics for the U.K. show scam and fraud spam running at 13 percent -- well below the global rate -- suggesting this category could see rises in the coming year.