nonillion vs septendecillion

nonillion

num

  • 10⁵⁴. 

  • 10³⁰. 

noun

  • An unspecified very large number. 

septendecillion

num

  • 10⁵⁴. 

  • 10¹⁰². 

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