insulate vs shelter

insulate

verb
  • To separate, detach, or isolate. 

  • To separate a body or material from others, e.g. by non-conductors to prevent the transfer of electricity, heat, etc. 

shelter

verb
  • To take cover. 

  • To provide cover from damage or harassment; to shield; to protect. 

noun
  • A refuge, haven or other cover or protection from something. 

  • An institution that provides temporary housing for homeless people, battered women, etc. 

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