catacomb vs lichyard

catacomb

noun
  • An underground system of tunnels and chambers with recesses for graves, used (in former times) as a cemetery; a tunnel system used for burying the dead, as in Paris or Ancient Rome. 

lichyard

noun
  • A graveyard. 

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