intensive care unit vs trauma centre

intensive care unit

noun
  • A hospital ward into which critically ill patients, in danger of dying, are admitted and closely monitored (abbreviation: ICU). 

trauma centre

noun
  • A specialized section of a hospital intended to treat suddenly occurring life-threatening injuries and medical conditions. 

  • A type of hospital with a highly capable trauma department. 

How often have the words intensive care unit and trauma centre occurred in a corpus of books? (source: Google Ngram Viewer )