garrote vs iron collar

garrote

verb
  • to execute by strangulation 

  • to kill using a garrote 

noun
  • an iron collar formerly used in Spain to execute people by strangulation 

  • something, especially a cord or wire, used for strangulation 

iron collar

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