coalman vs headsman

coalman

noun
  • Someone who delivers coal. 

  • A coal miner (as distinguished from other type of miners). 

  • Someone who sells coal. 

headsman

noun
  • A labourer in a colliery who transports the coal from the workings to the horseway, and who is oftentimes assisted by a younger worker called a foal. 

  • One in command of a whaling vessel. 

  • An executioner whose method of dispatching the condemned is decapitation. 

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