About 30,000 websites were hacked daily about a year ago. Without a shadow of a doubt, the number has grown immensely since then. Not all of these websites lose their data (i.e., user accounts and content). In fact, hacking is just one way of losing data.
For example, you can also lose data due to botched updates, corrupt hard drives, human error, and server hiccups. The solution to these issues is simple -- back up your data regularly.