nonillion vs skillion

nonillion

noun

  • An unspecified very large number. 

num

  • 10³⁰. 

  • 10⁵⁴. 

skillion

noun

  • Any indefinitely large number. 

  • A room built against the back of another building, having a separate roof. 

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