diva vs soloist

diva

noun
  • 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. 

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

soloist

noun
  • A person who performs a solo. 

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