Antivirus is the most common security technology [NB Awaiting more info]

According to research from the Computing Technology Industry Association, CompTIA, 95.5 per cent of organizations use some form of antivirus technologies.

Firewalls and proxy servers are the second most used technology, identified by 90.8 percent of respondents, a number down from last year, when 93.7 percent of organizations reported using the technologies.
 
Security audits and penetration testing accounted for increasing measures to monitor general security performance. They were identified by 61 per cent of respondents, up from 53 per cent.

Fifteen per cent of organizations reported they have no measures in place to monitor general security performance.

Other commonly used measures include systems baselines (51.4 percent, up from 46.5 percent) and change control tracking (44.3 percent, up from 39.1 percent).
 
www.comptia.org