Nana vs Oma

Nana

name
  • A Japanese female given name from Japanese 

  • One's grandmother. 

  • A governess. 

Oma

name
  • A female given name 

  • A town in Iron County, Wisconsin, United States. 

  • A township in Gêrzê County, Ngari, Tibet Autonomous Region, China. 

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