atone vs expiate

atone

verb
  • To make reparation, compensation, amends or satisfaction for an offence, crime, mistake or deficiency. 

  • To absolve (someone else) of wrongdoing, especially by standing as an equivalent. 

expiate

verb
  • To atone or make reparation for. 

  • To wind up, bring to an end. 

  • To make amends or pay the penalty for. 

  • To purify with sacred rites. 

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