balladeer vs troubadour

balladeer

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

verb
  • To sing a ballad 

troubadour

noun
  • An itinerant composer and performer of songs in medieval Europe; a jongleur or travelling minstrel. 

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