freshwater vs salt water

freshwater

noun
  • A body of fresh water 

adj
  • Consisting of fresh water. 

  • neoclassical, in reference to U.S. macroeconomics and economics departments near the Great Lakes. 

  • Unskilled as a seaman. 

  • Living in fresh water. 

salt water

noun
  • any water containing dissolved salt; brine 

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