gulag vs slammer

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. 

slammer

noun
  • jail, prison. 

  • One who, or that which, slams. 

  • One who competes in a poetry slam. 

  • A tequila cocktail that is slammed onto a surface to induce fizzing. 

  • One who takes part in slam-dance. 

  • In the game of Pogs, the heavier piece used to strike the stack of counters. 

  • A slam-door train. 

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