commiserate vs have mercy

commiserate

verb
  • To sympathize; condole. 

  • To offer condolences jointly with; express sympathy with. 

  • To feel or express compassion or sympathy for (someone or something). 

have mercy

verb
  • To show mercy or compassion; to stop inflicting punishment or a barrage. 

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