concordat vs dicker

concordat

noun
  • A formal agreement between two parties, especially between a church and a state; specifically, an agreement between the Pope and a government. 

dicker

noun
  • A chaffering, barter, or exchange, of small wares. 

verb
  • To bargain, haggle or negotiate over a sale. 

  • To barter. 

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