empathy vs hitting it off

empathy

noun
  • Capacity to understand another person's point of view or the result of such understanding. 

  • Identification with or understanding of the thoughts, feelings, or emotional state of another person. 

  • A paranormal ability to psychically read another person's emotions. 

hitting it off

How often have the words empathy and hitting it off occurred in a corpus of books? (source: Google Ngram Viewer )