dogface vs warfighter

dogface

noun
  • A foot soldier, especially during World War II. 

  • Either of two pierid butterflies of the New World genus Zerene. 

  • An ugly person. 

warfighter

noun
  • A soldier (especially of the United States military). 

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