replenish vs stock up

replenish

verb
  • To refill; to renew; to supply again or to add a fresh quantity to. 

stock up

verb
  • To acquire or increase stock or inventory. 

  • To swell up (usually refers to edema in a leg). 

  • To extirpate; to dig up. 

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