in full swing vs mushrooming

in full swing

prep
  • Proceeding fully, quickly, or completely; thoroughly begun and in progress. 

mushrooming

noun
  • Rapid or explosive growth. 

  • The formation of a mushroom-like shape. 

  • The act of gathering mushrooms. 

How often have the words in full swing and mushrooming occurred in a corpus of books? (source: Google Ngram Viewer )