chattel vs workhorse

chattel

noun
  • Tangible, movable property. 

  • A slave. 

workhorse

noun
  • Anyone or anything that does a lot of work; something or someone who works consistently or regularly. 

  • A horse used primarily for manual labor; a draft horse. 

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