aggravate vs eat away at

aggravate

verb
  • To exasperate; to provoke or irritate. 

  • To make (an offence) worse or more severe; to increase in offensiveness or heinousness. 

  • To make worse; to exacerbate. 

eat away at

verb
  • To cause to feel uneasy, troubled, worried, guilty, or vexed; to bother about something. 

  • To erode. 

  • To consume or use up, erode or wear away gradually. 

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