lady of leisure vs lady of light virtue

lady of leisure

noun
  • A female prostitute. 

  • An unemployed woman or one who has retired from work. 

  • A lady who is of independent means and so does not need employment; one who is free from duties and responsibilities. 

lady of light virtue

noun
  • A female prostitute. 

  • A woman with lax sexual morals; a slut. 

How often have the words lady of leisure and lady of light virtue occurred in a corpus of books? (source: Google Ngram Viewer )