finest hour vs heyday

finest hour

noun
  • A point in time or a relatively brief period of time when an especially distinguished, admirable, or effective set of actions is performed. 

  • 1979 August 2, Peter Calamai, "Analysis: It's brave words and bad vibrations," Edmonton Journal (Canada), p. D20 (retrieved 28 August 2013) 

  • 2010 Oct. 13, Tim Padgett, "Chile Celebrates As Miners Emerge from Underground," Time (retrieved 28 August 2013) 

  • 1940 June 18, "Churchill Says Hope Not Dead," San Jose Evening News, p. 1 (retrieved 28 August 2013) 

heyday

noun
  • A period of success, popularity, or power; prime. 

intj
  • A lively greeting. 

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