press conference vs round table

press conference

noun
  • A question-and-answer session with members of television, print and other media. 

round table

noun
  • A television show segment in which pundits or reporters discuss current events. 

  • A conference at which participants of similar status discuss and exchange views. 

  • Used other than figuratively or idiomatically: see round, table. 

How often have the words press conference and round table occurred in a corpus of books? (source: Google Ngram Viewer )