Idaho vs north forty

Idaho

name
  • A state in the western United States. Capital and largest city: Boise. 

  • An unincorporated community in Pike County, Ohio, United States, named for Idaho Territory. 

  • University of Idaho 

noun
  • In full Idaho potato: a variety of potato grown in Idaho, especially the Russet Burbank. 

north forty

noun
  • A 40-acre section of land, located in the northernmost part of a farm or ranch. 

  • Any remote place. 

  • Farms, ranches, or agricultural land collectively. 

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