Siberian vs ice-covered

Siberian

adj

  • Of or relating to Siberia. 

noun

  • A person from Siberia. 

  • A long-haired domestic cat breed. 

ice-covered

adj

  • covered with a layer of ice, e.g. water; frozen over 

How often have the words Siberian and ice-covered occurred in a corpus of books? (source: Google Ngram Viewer )