paradiddle vs pit-a-pat

paradiddle

verb
  • To produce percussive sounds of this kind. 

noun
  • A percussive exercise (one of 26 drum rudiments) which involves playing four even strokes in the order ‘right left right right’ or ‘left right left left’ 

pit-a-pat

verb
  • To make a series of quick tapping sounds; to palpitate 

noun
  • A series of quick tapping sounds 

adv
  • With a quick tapping sound 

How often have the words paradiddle and pit-a-pat occurred in a corpus of books? (source: Google Ngram Viewer )