pony keg vs state liquor agency

pony keg

noun
  • A container for beer holding 7.75 US gallons, equal to half the size of a standard beer keg. 

  • A drive-through liquor store; by extension, any convenience store. 

state liquor agency

How often have the words pony keg and state liquor agency occurred in a corpus of books? (source: Google Ngram Viewer )