kindness vs tenderness

kindness

noun
  • The state of being kind. 

  • An instance of kind or charitable behaviour. 

tenderness

noun
  • a tendency to express warm, compassionate feelings 

  • pain or discomfort when an affected area is touched 

  • concern for the feelings or welfare of others 

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