Billy vs Heinie

Billy

name
  • A diminutive of the male given name William. 

  • The B-25 twin-engine bomber aircraft used during World War Two, commonly called the "B-25 Mitchell" in honor of U.S. Army General William "Billy" Mitchell. 

Heinie

name
  • A diminutive form of Heinrich, or its English cognate Henry, sometimes applied to a person of (real or supposed) German heritage. 

noun
  • A German, especially a German soldier. 

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