Nana vs nana

Nana

name

  • One's grandmother. 

  • A governess. 

  • A Japanese female given name from Japanese 

nana

noun

  • A nanny. 

  • A banana. 

  • One's grandmother. 

  • A foolish person. 

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