correspondence vs fourth estate

correspondence

noun
  • Newspaper or news stories. 

  • A relation. 

  • Reciprocal exchange of civilities, especially conversation between persons by means of letters. 

  • Postal or other written communications. 

  • An agreement of situations or objects with an expected outcome. 

  • A similarity between physical and spiritual things (e.g. light to wisdom, or warmth to love) 

fourth estate

noun
  • Journalism or journalists considered as a group; the press. 

How often have the words correspondence and fourth estate occurred in a corpus of books? (source: Google Ngram Viewer )