earn vs earn one's crust

earn

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

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

  • To achieve by being worthy of. 

  • To receive payment for work. 

earn one's crust

verb
  • To earn money, to do something as a job. 

How often have the words earn and earn one's crust occurred in a corpus of books? (source: Google Ngram Viewer )