earn vs strike gold

earn

verb
  • To achieve by being worthy of. 

  • To cause (someone) to receive payment or reward. 

  • To receive payment for work. 

  • To gain (success, reward, recognition) through applied effort or work. 

strike gold

verb
  • To be lucky, to win or be successful. 

  • To find gold 

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