perversion vs rough trade

perversion

noun
  • A sexual practice considered abnormal; sexual deviance. 

  • The action of perverting someone or something; humiliation; debasement. 

  • The state of being perverted; depravity; vice. 

  • Distortion or corruption of the original course, meaning, or state of something. 

  • Tendril perversion. 

rough trade

noun
  • Violent or sadomasochistic sex, especially casual gay sex. 

  • Rough or tough men, either gay or straight, who are available as casual sexual partners for other men (for example in exchange for money). 

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