cracking vs prolonging

cracking

adj
  • Enjoyable. 

  • That cracks; that produces a sharp sound as of something splitting or breaking. 

  • Great. 

noun
  • The formation of cracks on a surface. 

  • The thermal decomposition of a substance, especially that of crude petroleum in order to produce petrol / gasoline. 

  • The production of a crack sound. 

adv
  • Very, usually associated with praise. 

prolonging

noun
  • prolongation 

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