diva vs superstar

diva

noun
  • Any female celebrity, usually a well known singer or actress. 

  • A person who may be considered or who considers herself (or by extension himself) much more important than others, has high expectations of others and who is extremely demanding and fussy when it comes to personal privileges. 

superstar

noun
  • Someone who has accumulated a vast amount of fame; a high-level celebrity. 

  • A giant star. 

  • An exceptionally productive employee. 

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