esky vs icehouse

esky

noun
  • An insulated picnic cooler, using ice or refrigerated blocks to keep food and drinks cool. 

icehouse

noun
  • A deep cellar or outdoor building used for the storage of ice or snow; sometimes also used to store food at low temperature. 

  • An ice hockey rink. 

  • A cold state in global climate. 

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