Except every day is World Backup Day. But that's as good an excuse to party as any. (you should read the article at the link, which offers great advice on how to keep from losing your data)
It's been a while since I've beat this drum, but you do know that backing up your data is perhaps the most important security act you can do? I thought you did.
Older posts on the topic:
The Most Important Part Of Computer Security (2010)
Back Up Your Data (2012)
Important Security Rule: Back Up Your Data (2013)
Where's Your Backup (2014, posted by co-blogger ASM826 who does this for a living)