insignia vs second lieutenant

insignia

noun
  • A patch or other object that indicates a person's official or military rank, or membership in a group or organization. 

  • A mark or token by which anything is known. 

  • A symbol or token of personal power, status, or office, or of an official body of government or jurisdiction. 

second lieutenant

noun
  • The lowest rank of a commissioned officer in the United States Army, United States Air Force, or United States Marine Corps, below a first lieutenant. The rank of second lieutenant is equivalent to the naval rank of ensign. 

  • The lowest rank of a commissioned army officer, below a lieutenant. 

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