The safest way to store your important personal data is to encrypt it.  This includes any backup copies, especially if you store them on a remote server.  

Encryption scrambles your data using a type of long password, called a key, and one of several available mathematical methods, called encryption algorithms.  This means even if someone managed to steal a copy of your file, they could not read it without the password, assuming you use a strong encryption algorithm and long password.  

It is easy to do, if you understand how to manage files on your PC.  To learn how, search file encryption in the help section of your PC.  

You can also use external USB personal security devices that have the capabilty to encrypt (scramble and protect with a password) your files with “industrial strength” levels of security.