caravansary vs caravanserai

caravansary

caravanserai

noun
  • A roadside inn having a central courtyard where caravans can rest. 

  • An upscale hotel. 

  • A home or shelter for caravans. 

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