megastore vs strip mall

megastore

noun
  • A large supermarket or similar retail outlet; a superstore. 

strip mall

noun
  • A shopping center consisting of a row of stores with separate entrances from the outdoors, typically along a road and/or with a parking lot in front. 

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