macadam vs tarmacadam

macadam

verb

  • To cover or surface with macadam. 

noun

  • The surface of a road consisting of layers of crushed stone (usually tar-coated for modern traffic). 

tarmacadam

verb

  • To cover or surface with tarmacadam. 

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