predate vs preexist

predate

verb
  • To exist or to occur before something else; to antedate. 

  • To prey upon something. 

  • To designate a date earlier than the actual one; to move a date, appointment, event, or period of time to an earlier point (contrast "postdate".) 

noun
  • A publication, such as a newspaper or magazine, that is issued with a printed date later than the date of issue. 

preexist

verb
  • To exist before something else. 

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