unconcern vs vivacity

unconcern

noun
  • Freedom from worry or apprehensiveness; insouciance or nonchalance. 

  • Lack of interest or care; indifference or apathy. 

vivacity

noun
  • The quality or state of being vivacious. 

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