cut down vs knock down

cut down

verb
  • To reduce the amount of something. 

  • To insult, to belittle. 

  • Used other than figuratively or idiomatically: see cut, down. 

  • To bring down by cutting. 

knock down

verb
  • To reduce the price of. 

  • To drink fast. 

  • To disassemble for shipment. 

  • To hit or knock (something or someone), intentionally or accidentally, so that it falls. 

  • To demolish. 

  • To approve a drinking toast by banging glasses on the table. 

  • At an auction, to declare (something) sold with a blow from the gavel. 

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