cooking with gas vs rigorous

cooking with gas

phrase
  • Functioning particularly effectively; achieving something substantial. 

  • With the updated software, I was really cooking with gas. I got the project done in half the time. 

  • Used other than figuratively or idiomatically: see cook, with, gas. 

rigorous

adj
  • Showing, causing, or favoring rigour/rigor; scrupulously accurate or strict; thorough. 

  • Severe; intense. 

How often have the words cooking with gas and rigorous occurred in a corpus of books? (source: Google Ngram Viewer )