burn the candle at both ends vs work too hard

burn the candle at both ends

verb
  • To waste something in two directions at once. 

  • To sleep late and wake up early; not well-rested. 

  • To work hard night and day. 

work too hard

How often have the words burn the candle at both ends and work too hard occurred in a corpus of books? (source: Google Ngram Viewer )