retain vs use up

retain

verb
  • To keep in possession or use. 

  • To employ by paying a retainer. 

  • To hold back (a pupil) instead of allowing them to advance to the next class or year. 

  • To keep in one's pay or service. 

  • To hold secure. 

use up

verb
  • to take or occupy 

  • to consume, deplete or exhaust 

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