assignee vs heiress

assignee

noun
  • one to whom rights or property is being transferred 

  • one to whom a thing is assigned 

  • one who is appointed to act or speak in place of another; an agent 

heiress

noun
  • A woman who has a right of inheritance or who stands to inherit. 

  • A woman who has received an inheritance. 

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