digging vs scavenging

digging

noun
  • The action performed by a person or thing that digs. 

  • A place where ore is dug, especially certain localities in California, Australia, etc. where gold is obtained. 

scavenging

noun
  • The act of searching through refuse for useful material. 

adj
  • That eats carrion 

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