hussar vs uhlan

hussar

noun
  • A member of the light cavalry of any of several European armies. 

  • A member of the national cavalry of Hungary, Croatia and Poland. 

uhlan

noun
  • A lancer, a soldier armed with a lance in a former light cavalry unit of the Polish, Prussian/German, Austrian, and Russian armies. 

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