quieten down vs unruffle

quieten down

verb
  • To make someone or something become quieter. 

  • To reduce intensity of an activity. 

  • To become quieter. 

unruffle

verb
  • To calm or soothe (a person). 

  • To calm down. 

  • To remove ruffles from; to make smooth. 

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