Firth vs Riverbank

Firth

name
  • A city and town in Idaho. 

  • A village in Nebraska. 

  • A surname. 

  • A small village in north-east Mainland, Shetland Islands council area, Scotland (OS grid ref HU4473). 

Riverbank

name
  • A city in Stanislaus County, California, United States. 

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