bowk vs retch

bowk

verb
  • To vomit. 

  • To belch, to burp. 

retch

verb
  • To make an unsuccessful effort to vomit; to strain, as in vomiting. 

noun
  • An unsuccessful effort to vomit. 

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