US Defense Department is still using 5.25'

[Costas]

Treasury's master business file, which contains all tax data on individual business income taxpayers, likewise is written in that same assembly language code, which was first used in the 1950s, and maintained on the old-school IBM mainframe.

http://www.cnbc.com/2016/05/25/us-military-uses-8-inch-floppy-disks-to-coordinate-nuclear-force-operations.html