gratify vs indulge

gratify

verb
  • To make content; to satisfy. 

  • To please. 

indulge

verb
  • To satisfy the wishes or whims of. 

  • To grant an extension to the deadline of a payment. 

  • To give way to (a habit or temptation); to not oppose or restrain. 

  • To grant as by favour; to bestow in concession, or in compliance with a wish or request. 

  • To yield to a temptation or desire. 

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