ear to the ground vs knowledgeable

ear to the ground

noun
  • Pursuing the practice or having the characteristic of carefully gathering information; well-informed. 

  • The practice or characteristic of carefully gathering information; a state or mindset of attentiveness. 

knowledgeable

noun
  • A person who has knowledge; an informed party. 

adj
  • Educated and well informed. 

  • Having knowledge, especially of a particular subject. 

How often have the words ear to the ground and knowledgeable occurred in a corpus of books? (source: Google Ngram Viewer )