accrue vs build up

accrue

verb
  • To accumulate. 

  • To become an enforceable and permanent right. 

  • To increase, to rise 

  • To reach or come to by way of increase; to arise or spring up because of growth or result, especially as the produce of money lent. 

  • To be incurred as a result of the passage of time. 

build up

verb
  • To accumulate, to pile up, to increase in stages. 

  • To close up by building. 

  • To strengthen. 

  • In solitaire card games, to place a card over another card of lower value. (e.g., place 5♦ over 4♣) 

  • To erect; to construct. 

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