go at vs peg away

go at

verb
  • To try to solve a problem a specific way; to undertake a task. 

  • Used other than figuratively or idiomatically: see go, at. 

  • To initiate an attack on or an argument with. 

peg away

verb
  • To keep working at something 

How often have the words go at and peg away occurred in a corpus of books? (source: Google Ngram Viewer )