naga vs serpent

naga

noun
  • A member of a class of semi-divine creatures, often taking the form of a very large snake and associated with water. 

  • A loincloth. 

serpent

noun
  • A snake, especially a large or dangerous one. 

  • An obsolete wind instrument in the brass family, whose shape is suggestive of a snake (Wikipedia article). 

  • A kind of firework with a serpentine motion. 

  • A subtle, treacherous, malicious person. 

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