irrecoverable vs irretrievable

irrecoverable

adj
  • That cannot be recovered from or made good; irremediable. 

  • Not recoverable; incapable of being recovered. 

irretrievable

adj
  • Not retrievable; irrecoverable; irreparable 

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