rat-a-tat-tat vs rat-tat

rat-a-tat-tat

noun
  • A series of short, sharp taps, especially made by knocking on a door, beating a drum, or firing an automatic weapon 

intj
  • A series of short, sharp taps, especially made by knocking on a door, beating a drum, or firing an automatic weapon 

rat-tat

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