date rape drug vs gamma-hydroxybutyrate

date rape drug

noun
  • In particular, the drug flunitrazepam ("roofies"). 

  • A drug with sedative, hypnotic, dissociative, and/or amnesiac effects which is used to assist in the commission of a sexual assault (date rape). 

gamma-hydroxybutyrate

noun
  • Any salt or ester of gamma-hydroxybutyric acid, especially the sodium or potassium salts used as the drug "fantasy". 

How often have the words date rape drug and gamma-hydroxybutyrate occurred in a corpus of books? (source: Google Ngram Viewer )