assistance vs ball and chain

assistance

noun
  • Aid; help; the act or result of assisting. 

ball and chain

noun
  • One's wife, as a symbol of restraint. 

  • A heavy iron ball attached to a prisoner's leg by a chain as a means of restraint. 

  • Anything that restricts one's freedom or opportunities. 

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