Over 80 per cent of all email traffic during the fourth quarter of 2005 was "abusive", according to newly published research.

Data from the Messaging Anti-Abuse Working Group (MAAWG) suggests that, assuming one abusive email for each dropped connection, the ratio of blocked or tagged inbound emails for each unaffected email delivered has increased to 5:6 or 85 per cent. 

The organisation's report for the fourth quarter of 2005 noted that, with more than 1.5 dropped connections for every unaffected email delivered, there were approximately 500 dropped connections for each mailbox. 

The MAAWG email metrics programme includes over 100 million mailboxes, providing a statistically significant sample. This first report includes metrics provided voluntarily by nine MAAWG member ISPs and network operators worldwide.

The organisation said that future reports will be expanded to include additional ISPs. The complete report is available from the MAAWG website.