U.S.A. vs Yankee land

U.S.A.

name

  • Dated spelling of USA. 

Yankee land

name

  • The United States. 

  • New England. 

  • The northern states region of the United States. 

How often have the words U.S.A. and Yankee land occurred in a corpus of books? (source: Google Ngram Viewer )