convenience store vs department store

convenience store

noun
  • A small retail store, often in a residential area, that carries a limited selection of items such as staples, junk food, and drugstore items, and which is open long hours for the convenience of shoppers. 

department store

noun
  • A large store containing many different departments, each of which deals in the sale of different goods or services. 

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