pluck up vs stir up

pluck up

verb
  • To summon positive emotion (especially courage); to muster. 

  • To remove or acquire by plucking from, for example, the ground; to pick up. 

  • To become more cheerful. 

stir up

verb
  • To arouse or excite (passion or action). 

  • To move or disturb slightly; to make turbid. 

  • To mix (ingredients) by stirring. 

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