computer vs iPad

computer

noun
  • A programmable electronic device that performs mathematical calculations and logical operations, especially one that can process, store and retrieve large amounts of data very quickly; now especially, a small one for personal or home use employed for manipulating text or graphics, accessing the Internet, or playing games or media. 

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 computer and iPad occurred in a corpus of books? (source: Google Ngram Viewer )