thee vs y'all

thee

verb
  • To address (a person) using the pronoun thee. 

  • To use the word thee. 

noun
  • The letter ⟨(⟩, which stands for the th sound /ð/ in Pitman shorthand. 

y'all

verb
  • To use the pronoun "y'all" (to). 

det
  • Your pl; y'all's 

  • The group spoken or written to. 

How often have the words thee and y'all occurred in a corpus of books? (source: Google Ngram Viewer )