hang up one's boots vs put out to pasture

hang up one's boots

verb
  • retire, call it a day 

put out to pasture

verb
  • To make someone retire, especially due to advancing age. 

  • To discontinue something. 

  • Used other than figuratively or idiomatically: see put out, to, pasture. 

How often have the words hang up one's boots and put out to pasture occurred in a corpus of books? (source: Google Ngram Viewer )