by degrees vs gently

by degrees

prep
  • In gradual steps; bit by bit. 

gently

adv
  • In a gentle manner; to a gentle degree. 

  • Without strong force or quickness: softly, lightly. 

  • From a gentle or high-class family. 

  • Quietly: without much noise or motion. 

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