cash in vs line one's pockets

cash in

verb
  • To profit from something; to take advantage of an opportunity in order to profit, especially financially. 

  • To die. 

  • To exchange for cash. 

line one's pockets

verb
  • To accumulate personal wealth, especially in an illegal or morally objectionable manner. 

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