decimate vs finish off

decimate

verb
  • To devastate: to reduce or destroy significantly but not completely. 

  • To replace a high-resolution model with another of lower but acceptable quality. 

  • To reduce to one-tenth: to destroy or remove nine-tenths of anything. 

  • To destroy or remove one-tenth of anything. 

finish off

verb
  • To kill. 

  • To finish completely. 

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