Belt vs Metropolis

Belt

name
  • A town in Montana 

  • A surname. 

Metropolis

name
  • A ghost town in Elko County, Nevada, United States. 

  • A city, the county seat of Massac County, Illinois, United States. 

  • a classical city site in Anatolia (Turkey). 

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