grave vs infernal regions

grave

noun
  • Death, destruction. 

  • Any place of interment; a tomb; a sepulcher. 

  • Deceased people; the dead. 

  • An excavation in the earth as a place of burial 

  • A written accent used in French, Italian, and other languages. è is an e with a grave accent (`). 

  • A count, prefect, or person holding office. 

adj
  • Serious, in a negative sense; important, formidable. 

  • Low in pitch, tone etc. 

  • Characterised by a dignified sense of seriousness; not cheerful. 

infernal regions

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