digging vs scavenge

digging

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

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

scavenge

verb
  • To collect and remove refuse, or to search through refuse, carrion, or abandoned items for useful material. 

  • To expel the exhaust gases from the cylinder of an internal combustion engine, and draw in air for the next cycle. 

  • To remove unwanted material from something, especially to purify molten metal by removing impurities. 

  • To feed on carrion or refuse. 

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