I beg your pardon vs how's that

I beg your pardon

phrase
  • A phrase used to express an apology for an action. 

  • A phrase used to ask for clarification of something said if it is unexpected, odd or seen as rude without context. 

  • A phrase used to request something, for example if a statement was not heard. 

how's that

phrase
  • Used to make an appeal to the umpire as to whether the batsman is out or not 

  • Used to ask someone to repeat something 

  • Used other than figuratively or idiomatically: see how, is, that. 

How often have the words I beg your pardon and how's that occurred in a corpus of books? (source: Google Ngram Viewer )