burp vs cough up

burp

verb
  • To utter by burping 

  • To cause someone (such as a baby) to burp. 

  • To open (a container of fermenting substance) to allow the release of accumulated gas. 

  • To emit a burp. 

noun
  • A belch. 

cough up

verb
  • To spill, to fumble 

  • to hand over, give. 

  • to expel from the lungs, throat, etc. by coughing 

  • to lose a competition by one's own mistakes, usually near the end of the contest 

  • to pay, disburse 

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