accrue vs add 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. 

add up

verb
  • To accumulate; to amount to. 

  • To take the sum of; to total. 

  • To make sense; to be reasonable or consistent. 

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