gangster vs yakuza

gangster

noun
  • A member of a criminal or street gang. 

  • A member of a professional criminal organization; a racketeer. 

verb
  • To act like a gangster; to commit street crime or run a racket. 

yakuza

noun
  • A member of a Japanese organized crime gang. (plural: yakuzas) 

  • A Japanese organized crime gang. (plural: yakuza) 

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