quisling vs traditor

quisling

noun
  • A traitor who collaborates with the enemy. 

traditor

noun
  • A deliverer; a name of infamy given to Christians who delivered the Scriptures, or the goods of the church, to their persecutors to save their lives. 

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