Nearly 95 percent of the e-mail sent in 2007 has been "spam," junk advertising loathed by its recipients, according to a report released Wednesday by a US Web security firm.

The amount of junk e-mail has skyrocketed despite a 2004 US CAN-SPAM Act that placed restrictions on sending unwanted messages and sanctioned penalties for "spammers," according to California-based Barracuda Networks Inc.

Junk messages made up an estimated 70 percent of e-mail the year the act was passed, the Barracuda report indicates.

Barracuda said it based its findings on analysis of more than a billion e-mail messages received daily by its approximately 50,000 customers worldwide.

Spammers cunningly hide their identities by routing e-mails through other people's websites, blogs or computers, according to Barracuda.