boogie-woogie vs ragtime

boogie-woogie

noun
  • A style of blues piano music. 

  • A style of swing dance. 

ragtime

noun
  • A piece of music in this style. 

  • A musical form having a rhythm characterized by strong syncopation in the melody with a regularly accented accompaniment. 

How often have the words boogie-woogie and ragtime occurred in a corpus of books? (source: Google Ngram Viewer )