insensitivity vs unconcern

insensitivity

noun
  • The condition of being insensitive 

unconcern

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

  • Lack of interest or care; indifference or apathy. 

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