conserve vs shelter

conserve

verb
  • To protect an environment, heritage, etc. 

  • To remain unchanged during a process 

  • To save for later use, sometimes by the use of a preservative. 

noun
  • Wilderness where human development is prohibited. 

  • A jam or thick syrup made from fruit. 

shelter

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

  • To take cover. 

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 conserve and shelter occurred in a corpus of books? (source: Google Ngram Viewer )