inquiry vs third degree

inquiry

noun
  • The act of inquiring; a seeking of information by asking questions; interrogation; a question or questioning. 

  • Search for truth, information, or knowledge; examination of facts or principles; research; investigation 

third degree

noun
  • Intensive rough interrogation in order to extract information or a confession 

How often have the words inquiry and third degree occurred in a corpus of books? (source: Google Ngram Viewer )