cooler bag vs freezer

cooler bag

noun
  • Insulated bag used to keep food items cool for a limited amount of time (for example on the way from a grocery store to one's house). 

freezer

noun
  • An appliance or room used to store food or other perishable items at temperatures below 0° Celsius (32° Fahrenheit). 

  • A Parkinson's disease patient that experiences freezing of gait (FOG) episodes. 

  • The section of a refrigerator used to store food or other perishable items at a temperature below 0° Celsius (32° Fahrenheit). 

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