balladeer vs sonneteer

balladeer

noun
  • A singer, particularly a professional singer who performs ballads. 

verb
  • To sing a ballad 

sonneteer

noun
  • A writer of sonnets or small poems. 

verb
  • To compose sonnets. 

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