appreciation vs gratefulness

appreciation

noun
  • The act of appreciating. 

  • A rise in value. 

  • A fair valuation or estimate of merit, worth, weight, etc.; recognition of excellence; gratitude and esteem. 

  • Accurate perception; true estimation. 

gratefulness

noun
  • The state of being grateful. 

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