Spam levels reached 97.02 per cent in December 2007 and viruses accounted for 0.11 per cent of email traffic, new monitoring data reveals.

The figures suggest that less than three per cent of all email sent during the month was legitimate.

SoftScan warned today that, despite several high profile arrests and successful court cases throughout the year, spammers still have the upper hand over law enforcement.

"Once again the rapid increase of spam throughout 2007 demonstrates that there is not enough deterrent for spammers to give up their highly lucrative enterprise," said Diego d'Ambra, chief technology officer at SoftScan.

"Usually, when you look through our monthly statistics, you can quickly identify the weekends or major public holidays when there is less legitimate business email sent as the spam levels jump-up.

"But in December, except for some slightly lower levels in the first week, spam has remained consistently high throughout the month."

The extreme sustained level of spamming could be attributed to less legitimate email being sent because so many people take time off work during December.

But d'Ambra believes that this is unlikely as SoftScan's monitoring has not noticed this trend before in December or in the summer holiday months.

The top five virus families in December 2007 were:

1. Phishing: 87.54%
2. Dropper: 4.76%
3. Agent: 2.19%
4. Netsky: 1.24%
5. Downloader: 0.86%