Bastille vs gulag

Bastille

name
  • A prison in France, the storming of which in 1789 CE began the French Revolution. 

gulag

noun
  • A prison camp, especially one used to hold political prisoners. 

  • Also GULAG: the system of all Soviet labour camps and prisons in use, especially during the Stalinist period (1930s–1950s). 

  • A place where, or political system in which, people with dissident views are routinely oppressed. 

verb
  • To compel (someone) into a forced labour camp or a similar place of confinement or exile. 

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