Mister vs prexy

Mister

noun
  • Official form of address of a president of a nation. 

  • General title or respect of an adult male. 

  • Formal address to any official of an organization. 

  • A warrant officer or cadet in the United States Military Academy at West Point. 

  • An informal title used before a nickname or other moniker. 

  • Official title of a military man, usually anyone below rank of captain. 

prexy

noun
  • A president, especially of a college or university. 

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