Although more users seem to be wiping hard drives before selling them as second-hand, seven out of ten disks examined still contain data that can be reconstructed, a study commissioned by O&O Software said Tuesday.

The Berlin, Germany-based maker of hard drive utilities followed up its 2004 study by buying 200 disks on online auction site eBay, then examining the drives for evidence of recoverable data. More than 71 percent of the disks held data that the company could rebuild.

Among the data O&O was able to pull off the second-hard drives was internal memos and legal correspondence of an unnamed government agency, credit ratings from a drive once owned by a major German bank, and a goldmine of documents related to accusations of fraud and embezzlement at a mid-sized company.

In the similar study O&O did in 2004, researchers discovered 88 percent of 100 disks bought on eBay contained recoverable data.

"The results in 2004 were alarming," the report said. "In 2005, the results show a small improvement. However, even when the percentage of recoverable data on the tested hard disks has fallen, the 'quality' of recovered data has improved dramatically."

Hard drives aren't the only storage devices that can hold sensitive data which users may neglect to wipe off the hardware before tossing, recycling, or selling it, O&O went on. Mobile phones, USB flash drives, and even music players, which allow non-audio data to be stored on their drives or in their non-volatile memory, also need attention, said O&O.

The full report can be read in PDF format from O&O's Web site.