overman vs personal assistant

overman

noun
  • A person who supervises others; a supervisor, especially in a mine. 

  • A person with great powers; a superman. 

verb
  • To provide with too many personnel; overstaff. 

personal assistant

noun
  • Someone whose job is to assist and organize someone else's day-to-day business or personal tasks. 

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