conserve vs imperil

conserve

noun
  • Wilderness where human development is prohibited. 

  • A jam or thick syrup made from fruit. 

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. 

imperil

verb
  • To put into peril; to place in danger. 

  • To risk or hazard. 

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