haha vs hahaha

haha

intj
  • An onomatopoeic representation of laughter. 

verb
  • To laugh. 

noun
  • Type of boundary to a garden, pleasure-ground, or park, designed not to interrupt the view and to be invisible until closely approached. 

  • A large leafy Hawaiian plant, Gunnera petaloidea. 

hahaha

intj
  • haha (an onomatopoeic representation of laughter). 

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