tell tales out of school vs tittle-tattle

tell tales out of school

verb
  • To reveal confidential or sensitive information; to gossip. 

tittle-tattle

verb
  • To spread gossip. 

  • To engage in such gossip. 

noun
  • An idle, trifling talker; a gossip. 

  • petty, idle gossip. 

How often have the words tell tales out of school and tittle-tattle occurred in a corpus of books? (source: Google Ngram Viewer )