Free State vs Orange Free State

Free State

name
  • A province of South Africa. Capital: Bloemfontein, formerly Orange Free State. 

  • The Irish Free State. 

  • A nickname for Maryland. 

  • Irish republican term for the present-day Republic of Ireland. 

Orange Free State

name
  • A former province of South Africa (1910–1994), now the province of Free State. 

  • A former independent Boer republic in southern Africa (1854–1902). 

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