holier-than-thou vs pecksniffian

holier-than-thou

adj
  • Hypocritically or self-righteously pious; sanctimonious. 

pecksniffian

adj
  • Of or pertaining to Pecksniffery; unctuously hypocritical; sanctimonious. 

How often have the words holier-than-thou and pecksniffian occurred in a corpus of books? (source: Google Ngram Viewer )