fiacre vs hackney cab

fiacre

noun
  • A small horse-drawn carriage for hire; a hackney carriage. 

hackney cab

noun
  • A hackney carriage, a carriage pulled by a hackney horse, available for public hire. 

  • A motorised vehicle available for public hire; a black cab. 

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