Pirate vs caboose

Pirate

noun
  • someone connected with Bristol Rovers Football Club, as a fan, player, coach etc. 

  • someone connected with any of a number of sports teams known as the Pirates, as a fan, player, coach etc. 

caboose

noun
  • The person or team in last place. 

  • A youngest child who is born after a long gap in time. 

  • A small sand-filled container used as an oven on board ship. 

  • The last car on a freight train, having cooking and sleeping facilities for the crew; a guard’s van. 

  • buttocks 

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