holding cell vs slammer

holding cell

noun
  • A cell in a police station or courthouse in which a prisoner is held temporarily, pending charge, trial or sentencing. 

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 holding cell and slammer occurred in a corpus of books? (source: Google Ngram Viewer )