break of day vs sundown

break of day

noun
  • Daybreak. 

sundown

noun
  • Sunset. 

  • A hat with a wide brim to shade the eyes from sunlight. 

verb
  • to experience an episode or an onset of some detrimental mental condition like agitation, anxiety, hallucination or dementia, daily at nightfall. 

How often have the words break of day and sundown occurred in a corpus of books? (source: Google Ngram Viewer )