amass vs stow away

amass

verb
  • To collect into a mass or heap. 

  • to gather a great quantity of; to accumulate. 

  • To accumulate; to assemble. 

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 amass and stow away occurred in a corpus of books? (source: Google Ngram Viewer )