chills vs shivering

chills

noun
  • A biological response to being tickled; being cold; or experiencing fear, euphoria or sexual arousal in which the person forms goose bumps. 

  • A feeling of being cold, a symptom of many conditions. 

shivering

noun
  • The action of a person or thing that shivers; a trembling. 

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