aidman vs corpsman

aidman

noun
  • An army medical corpsman attached to a field unit. 

corpsman

noun
  • A hospital corpsman. 

  • An enlisted person in the U.S. Army who works as a field medic. 

  • A military medic. 

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