swap out vs take on

swap out

verb
  • To exchange (something or someone) for an unused (or less-used) equivalent. 

  • To exchange (something) for (something else). (usually followed by with or for) 

  • To transfer (memory contents) into a swap file. 

noun
  • Anything that is swapped out for another; an exchange. 

  • A pre-prepared food item used in place of an unfinished food item in order to cut down the overall preparation time during filming. 

take on

verb
  • To obtain the services of (a person) in exchange for remuneration; to give someone a job. 

  • To assume or take responsibility for. 

  • To (attempt to) dribble round (an opposition player). 

  • To catch on, do well; to become popular. 

  • To begin to have or exhibit. 

  • To attempt to fight, compete with, or engage with. 

  • To acquire, bring in, or introduce. 

  • To grieve or be concerned (about something or someone). 

How often have the words swap out and take on occurred in a corpus of books? (source: Google Ngram Viewer )