knock down vs put someone's lights out

knock down

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

  • To drink fast. 

  • To disassemble for shipment. 

  • To reduce the price of. 

  • 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. 

put someone's lights out

verb
  • To cause someone to become unconscious, especially by striking him or her. 

How often have the words knock down and put someone's lights out occurred in a corpus of books? (source: Google Ngram Viewer )