dawn vs oh dark hundred

dawn

noun
  • The morning twilight period immediately before sunrise. 

  • The rising of the sun. 

  • The earliest phase of something. 

  • The time when the sun rises. 

verb
  • To begin to give promise; to begin to appear or to expand. 

  • To begin to brighten with daylight. 

  • To start to appear or be realized. 

oh dark hundred

noun
  • Some unspecified hour in the early morning (implies an unpleasant time to be awake) 

How often have the words dawn and oh dark hundred occurred in a corpus of books? (source: Google Ngram Viewer )