drop off vs wake up

drop off

verb
  • To fall asleep. 

  • To fall. 

  • To deliver; to deposit or leave; to allow passengers to alight. 

  • To lessen or reduce. 

wake up

verb
  • To awake. 

  • To awaken somebody. 

  • To become more aware of a real-life situation; to concentrate on the matter in hand. 

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