expiration vs introduction

expiration

noun
  • The act of expiring. 

  • That which is produced by breathing out, as a sound. 

  • A cessation, extinction, ending 

  • Emission of volatile matter; exhalation. 

  • The last emission of breath; death. 

  • The act or process of breathing out, or forcing air from the lungs through the nose or mouth 

introduction

noun
  • The act or process of introducing. 

  • A written or oral explanation of what constitutes the basis of an issue. 

  • A means, such as a personal letter, of presenting one person to another. 

  • An initial section of a book or article, which introduces the subject material. 

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