nonpublic vs off the grid

nonpublic

adj
  • Not open to the public; not available to or shared by the public; private. 

off the grid

adj
  • Isolated; in a remote location; in seclusion; not participating in some official process or system. 

  • Not connected to a publicly available communication system, such as the World Wide Web or a mobile telephone network. 

  • Not using electricity from the public electrical supply system. 

adv
  • Secretly; in a clandestine manner. 

  • In or into a situation or place in which electricity from the public electricity system is not used. 

  • In or into a clandestine or isolated situation or place, especially one in which public communication is curtailed. 

How often have the words nonpublic and off the grid occurred in a corpus of books? (source: Google Ngram Viewer )