courtesanship vs sex work

courtesanship

noun
  • The state of being a courtesan; harlotry. 

sex work

noun
  • Any job in which sex or eroticism is involved, especially prostitution or pornography. 

  • My mother distributes condoms and outreach materials to those that do sex work for a living in the Tenderloin and Mission. 

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