Yank vs Zip

Yank

noun
  • A Yankee, a Northerner: someone from the Northern United States, especially from New England. 

  • An American: someone from the United States. 

Zip

noun
  • A Sicilian or Italian Mafioso who is relatively new to the United States. 

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