dispassion vs serenity

dispassion

noun
  • Freedom from passion; the absence of passion; an undisturbed state; apathy. 

serenity

noun
  • The state of being serene; calmness; peacefulness. 

  • A lack of agitation or disturbance. 

  • A title given to a reigning prince or similar dignitary. 

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