prostitution vs rough trade

prostitution

noun
  • Engaging in sexual activity with another person in exchange for goods (not necessarily money) or services. 

  • Debasement for profit or impure motives. 

  • Engaging in sexual activity with another person for pay. 

rough trade

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

  • Violent or sadomasochistic sex, especially casual gay sex. 

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