In its , titled "Data Breaches: The Insanity Continues," the non-profit ITRC found that 19.5 percent of reported breaches were due to hacking, with insider theft as the second most common cause at 16.9 percent. For the past two years, "data on the move," a typically human-error loss of a portable devices such as laptops or even briefcases, was the most common reported cause.

The ITRC is careful to note that its statistics are based on incomplete data, as differing laws and practices among different states mean that some breaches are not reported publicly, and the cause of the breach is not listed for about one third of those that are reported.

But according to the data available, the number of reported data breaches dropped since 2008, but was still more than in 2007. Last year, there were 498 breaches recorded by the ITRC, with and 446 in 2007.

With 41.2 percent of reported breaches, the business sector was the most likely to suffer a breach. But "the financial and medical industries, perhaps due to stringent regulations, maintain the lowest percentage of breaches," according to the report.

The ascendance of hacking as the prime data breach cause underscores a troubling point. As the ITRC report states, a data breach does not equal identity theft. A state might require a company to report a lost laptop with sensitive data as a data breach, particularly if the data was foolishly stored unencrypted. But that data might never be used for nefarious purposes, and might simply be ignored or even deleted by the laptop's finder or thief.