But mining remains the industry most affected by spam with a 56 percent spam rate, second to manufacturing and construction, the report said.
Spam may be innocuous and annoying to many, but unwanted emails can come with attached malware and links that generate money when clicked.
The drop in spam and phishing related emails suggests cyberattackers are focusing their efforts on other ways to generate money. Malware-based attacks, and ransomware and crypto-ransomware -- where files are locked and encrypted for a fee -- are on the rise.
"This increase in activity lends more evidence to the idea that, with the continued drops in email-based malicious activity, attackers are simply moving to other areas of the threat landscape," said Symantec's Ben Nahorney in the report.
In the past few years, police and law enforcement have continually targeted spam networks with take-downs and raids. But private industry, notably email providers like Google, have also begun working to reduce the amount of spam that reaches inboxes.
The search giant's latest trick, dubbed machine learning, to determine which messages should be marked as spam is helping to keep less than 0.1 percent of email in the average Gmail inbox as spam.