haunted vs unusual

haunted

adj
  • Showing a feeling of being disturbed. 

  • Of a location, frequented by a ghost or ghosts. 

  • Obsessed (by an idea, threat, etc.). 

unusual

adj
  • Not usual, out of the ordinary. 

noun
  • Something that is unusual; an anomaly. 

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