gurney vs palanquin

gurney

noun
  • A stretcher having wheeled legs. 

palanquin

noun
  • A covered type of litter for a stretched-out passenger, carried on four poles on the shoulders of four or more bearers, as formerly used (also by colonials) in eastern Asia. 

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