dumpster diving vs skipping

dumpster diving

noun
  • The act of recovering, for any purpose, discarded items that would otherwise be sent to a landfill. 

skipping

noun
  • The act by which something is skipped or omitted. 

  • The game, activity, or exercise of jump rope. 

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