portent vs presage of the end

portent

noun
  • A portending; significance 

  • Something regarded as portentous; a marvel; prodigy. 

  • Something that portends an event about to occur, especially an unfortunate or evil event; an omen. 

presage of the end

How often have the words portent and presage of the end occurred in a corpus of books? (source: Google Ngram Viewer )