cocaine vs crack (cocaine)

cocaine

noun
  • An addictive drug derived from coca (Erythroxylum) or prepared synthetically, used sometimes medicinally as a local anesthetic and, often illegally, as a stimulant. 

  • Any derivative of cocaine. 

crack (cocaine)

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