bagger vs courtesy clerk

bagger

noun
  • A retail employee who bags customers' purchases and carries them to the customers' vehicles. 

  • One who bags. 

  • A touring motorcycle equipped with saddlebags. 

courtesy clerk

noun
  • Synonym of bagger (“retail employee who bags customers' purchases”) 

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