infernal vs pitch dark

infernal

adj
  • Very annoying; damned. 

  • Of or relating to hell, or the world of the dead; hellish. 

  • Of or relating to a fire or inferno. 

  • Stygian, gloomy. 

  • Diabolical or fiendish. 

pitch dark

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