endanger vs preserve

endanger

verb
  • To put (someone or something) in danger; to risk causing harm to. 

preserve

verb
  • To save from decay by the use of some preservative substance, such as sugar or salt; to season and prepare (fruits, meat, etc.) for storage. 

  • To maintain throughout; to keep intact. 

  • To protect; to keep from harm or injury. 

noun
  • An activity with restricted access. 

  • A sweet spread made of any of a variety of fruits. 

  • A reservation, a nature preserve. 

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