cultivar vs diversity

cultivar

noun
  • A cultivated (not necessarily botanical) variety of a plant species or hybrid of two species. 

diversity

noun
  • A variety; diverse types or examples. 

  • Equal-opportunity inclusion. 

  • The quality of being diverse or different; difference or unlikeness. 

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