Caucasian vs pigskin

Caucasian

noun
  • A white person. 

  • A group of languages spoken in the Caucasus region. 

  • A native or inhabitant of the Caucasus. 

  • Synonym of White Russian (“a cocktail consisting of coffee liqueur, milk, and vodka”) 

adj
  • Of or relating to the Caucasus region or its culture, languages, and people. 

  • Of a person: having a white complexion and European ancestry; white. 

pigskin

noun
  • Leather made from the skin of a pig. 

  • The skin of a pig. 

  • A football. 

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