boards vs tear-jerker

boards

noun
  • A hardcover binding on a book. 

  • Examinations given for entry to college or to qualify for a profession. 

  • A stage (as in a theater). 

  • Structure around a rink for ice hockey. 

tear-jerker

How often have the words boards and tear-jerker occurred in a corpus of books? (source: Google Ngram Viewer )