niece vs paternal aunt

niece

noun
  • A daughter of one’s cousin or cousin-in-law 

  • A daughter of one’s sibling, brother-in-law, or sister-in-law; either the daughter of one's brother ("fraternal niece"), or of one's sister ("sororal niece"). 

paternal aunt

noun
  • A sister of someone’s father. 

  • The wife of a sibling of someone’s father. 

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