dealing vs exchange of contracts

dealing

noun
  • A business transaction. 

  • One's manner of acting toward others; behaviour; interactions or relations with others. 

exchange of contracts

noun
  • The act of exchanging contracts. 

  • The point or stage at which a conveyancing contract comes into existence between negotiating parties for the carrying out of a disposition of an estate in land; usually requiring the payment of a deposit. 

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