topple vs unhorse

topple

verb
  • To push or throw over 

  • To overturn 

  • To overthrow something. 

  • To totter and fall, or to lean as if about to do so. 

unhorse

verb
  • To disrupt or unseat; to remove from a position. 

  • To forcibly remove from a horse. 

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