interrogate vs want to know

interrogate

verb
  • to question or quiz, especially in a thorough and/or aggressive manner 

  • to examine critically. 

  • to query; to request information from. 

want to know

verb
  • To ask (used as a dialogue marker or introductory statement). 

How often have the words interrogate and want to know occurred in a corpus of books? (source: Google Ngram Viewer )