innards vs solar plexus

innards

noun
  • The internal organs of a human or animal; especially viscera, intestines. 

  • The inner workings of something; the insides or guts. 

solar plexus

noun
  • A complex network of nerves and ganglia, located within the abdomen behind the stomach. 

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