According to the 2013 Cost of a Data Breach Report by Symantec and the Ponemon Institute, human errors and system problems caused 64 percent of data breaches in 2012 (h/t Computer Weekly).

The global average cost of a data breach rose to $136 per record in 2012, according to the report, though the cost per data breach incident in the United States was down slightly at $5.4 million. The reported attributed the drop to the appointment of CISos, comprehensive incident response plans, and stronger overall security programs.

Still, the U.S. and Germany incurred the most costly data breaches in 2012, with an average cost per compromised record of $188 and $199, respectively.

"While external attackers and their evolving methods pose a great threat to companies, the dangers associated with the insider threat can be equally destructive and insidious," Ponemon Institute chairman Larry Ponemon said in a statement. “Eight years of research on data breach costs has shown employee behavior to be one of the most pressing issues facing organizations today, up 22 percent since the first survey.”

"Given organizations with strong security postures and incident response plans experienced breach costs 20 percent less than others, the importance of a well-coordinated, holistic approach is clear," Anil Chakravarthy, executive vice president of the Information Security Group, Symantec, said in a statement. "Companies must protect their customers' sensitive information no matter where it resides, be it on a PC, mobile device, corporate network or data center."