“In 2009, ICS-CERT fielded 9 incident reports. In 2010, that number increased to 41. In 2011, it was 198. Of those 198, seven resulted in the deployment of onsite incident response teams from ICS-CERT, and 21 of the other incidents involved remote analysis efforts by the Advanced Analytics Lab. Incidents specific to the water sector, when added to those that impacted multiple sectors, accounted for more than half of the incidents due to a larger number of Internet-facing control system devices reported by independent researchers, according to the report.”
Source:U.S. Critical Infrastructure Cyber Attack Reports Jump Dramatically – Dark Reading