bend over backwards vs have one’s nose to grindstone

bend over backwards

verb
  • Used other than figuratively or idiomatically: see bend over, backwards. 

  • To make a great effort; to take extraordinary care; to go to great lengths. 

have one’s nose to grindstone

How often have the words bend over backwards and have one’s nose to grindstone occurred in a corpus of books? (source: Google Ngram Viewer )