Z vs izzard

Z

noun
  • Z-drug. 

  • A member of Generation Z. 

character
  • The twenty-sixth letter of the English alphabet, called zed or zee and written in the Latin script. 

izzard

noun
  • The letter Z; zed, zee. 

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