flip one's wig vs have bats in one's belfry

flip one's wig

verb
  • To act in an irrational manner or appear to be temporarily insane. 

  • To be very angry. 

have bats in one's belfry

verb
  • To be crazy or eccentric. 

How often have the words flip one's wig and have bats in one's belfry occurred in a corpus of books? (source: Google Ngram Viewer )