cough drop vs iPad

cough drop

noun
  • A small, medicated tablet intended to be dissolved slowly in the mouth to relieve coughing symptoms temporarily. 

iPad

noun
  • Any lightweight low-power tablet computer. 

  • A lightweight low-power tablet computer of a particular range from Apple Inc. 

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