According to a report by the London Daily Mail, the figures were released to technology consulting firm Lewis Communications under the U.K.'s Freedom of Information Act.
In all, a total of 340 laptops, 593 CDs, DVDs, and floppy disks, 215 USB memory sticks, 96 removable hard disk drives, and 13 mobile phones have disappeared from the Ministry of Defense during the two-year time period investigated.
Only one in five of the devices that disappeared was encrypted, leading security experts to criticize the "cavalier attitude" about the protection of data.
The MoD had the worst record of 11 government departments studied.
In all, the 11 ministries reported the loss of 518 laptops, 131 BlackBerrys or iPhones, 104 mobile devices, and 932 electronic storage devices over the past two years.
The figures suggest the MoD's record has not improved significantly since July 2008, when it admitted that 658 laptops had been stolen and 89 lost in the previous four years, the report says.
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