buy up vs stow away

buy up

verb
  • To buy off; to pay in blackmail money or similar. 

  • To buy the whole of; to purchase the entire stock of something. 

  • To buy whatever is available of something. 

stow away

verb
  • to stow or secure aloof in a safe place 

  • to obtain passage (on a ship or similar vehicle) by secreting oneself inside before departure 

How often have the words buy up and stow away occurred in a corpus of books? (source: Google Ngram Viewer )