buy into vs earn

buy into

verb
  • To believe; to accept a craze or fad as valid. 

  • To buy stocks or shares of (a business). 

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. 

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