Scientific Data Disappears At Alarming Rate, 80% Lost In Two Decades. Another data point in the weirdness that is exponential growth. 

So. Data generation is rising exponentially. Total long term storage is rising exponentially, but slower. So it's no surprise that the rate of forgetting data is also rising exponentially.

Yes, folks, we're forgetting more data than ever before.

And that's before you hit the problems of obsolete data formats and data storage mechanisms; EBCDIC data on 8" CPM floppies? Displaywrite 4 on Zip disks? And then there's storage that self destructs. Silent movies on celluloid is one thing, but even CDs degrade eventually.
http://science.slashdot.org/story/13/12/20/0314239/scientific-data-disappears-at-alarming-rate-80-lost-in-two-decades