Puritan vs freethinker

Puritan

noun
  • A member of a particular Protestant religious sect advocating greater purity and piety. 

freethinker

noun
  • A person who has formed his or her opinions using reason and rational enquiry; somebody who has rejected dogma, especially with regard to religion. 

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