presentiment vs unconcern

presentiment

noun
  • A premonition; a feeling that something, often of undesirable nature, is going to happen. 

unconcern

noun
  • Lack of interest or care; indifference or apathy. 

  • Freedom from worry or apprehensiveness; insouciance or nonchalance. 

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