foretoken vs forewarning

foretoken

noun
  • A prognostic; a premonitory sign; warning or presentiment. 

verb
  • To betoken beforehand; prognosticate; foreshadow; give warning of; presage. 

forewarning

noun
  • An advance warning; an omen. 

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