foreign currency vs shilling

foreign currency

noun
  • Any currency that is in use in a foreign nation, and an authorized medium of circulation and the basis for record-keeping in that nation. 

shilling

noun
  • A currency in the United States, differing in value between states. 

  • A coin formerly used in the United Kingdom, Ireland, Malta, Australia, New Zealand and many other Commonwealth countries worth twelve old pence, or one twentieth of a pound sterling. 

  • The currency of Kenya, Somalia, Tanzania and Uganda. 

  • The Spanish real, formerly having the value of one eighth of a dollar. 

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