call girl vs moll

call girl

noun
  • A female prostitute who is hired by telephone. 

  • A woman who works as a call center agent. (see usage notes) 

moll

noun
  • A female companion of a gangster, especially a former or current prostitute. 

  • A girlfriend of a surfie; blends with pejorative sense. 

  • A female fan of extreme metal, grunge or hardcore punk, especially the girlfriend of a musician of those aforementioned genres. 

  • A girlfriend of a bikie. 

  • A prostitute or woman with loose sexual morals. 

  • Bitch, slut; an insulting epithet applied to a female. 

How often have the words call girl and moll occurred in a corpus of books? (source: Google Ngram Viewer )