author vs writer

author

noun
  • The originator or creator of a work, especially of a literary composition. 

  • Someone who writes books for a living. 

verb
  • To create a work as its author. 

writer

noun
  • A person who writes, or produces literary work; an author can refer to themself as "the writer". 

  • An ordinary legal practitioner in Scottish country towns. 

  • A petty officer in the United States navy who keeps the watch-muster and other books of the ship. 

  • A clerk of a certain rank in the service of the East India Company, who, after serving a certain number of years, became a factor. 

  • A graffiti artist. 

  • Anything that writes or produces output. 

  • The seller of an option. 

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