Nan vs Nanna

Nan

name
  • A diminutive of the female given name Ann and Nancy. 

  • A province of Thailand. 

  • A city in Thailand. 

Nanna

name
  • A goddess, the wife of Balder. 

  • A surname from Italian. 

  • The god of the moon in Sumerian mythology. 

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