Swarga vs Valhalla

Swarga

name

  • Heaven, Paradise 

  • Indra's abode 

Valhalla

noun

  • An abode of the gods or afterlife in general. 

name

  • The home of half of all warriors who died gloriously in battle as well as many of the Æsir. 

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