piety vs sky daddy

piety

noun
  • A devout act or thought. 

  • Reverence and devotion to God. 

  • A belief that is accepted unthinkingly and with undue reverence. 

  • Similar reverence to one's parents and family or to one's country. 

sky daddy

noun
  • A god, especially (derogatory, offensive) God the Father. 

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