preexistent vs premature

preexistent

adj
  • Preceding existence. 

  • Existing previously. 

premature

adj
  • Occurring before a state of readiness or maturity has arrived. 

  • Taking place earlier than anticipated, prepared for, or desired. 

  • Suffering from premature ejaculation. 

noun
  • An infant born prematurely. 

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