parlay vs rack up

parlay

verb
  • To increase (an asset, money, etc.) by gambling or investing in a daring manner. 

  • To carry forward the stake and winnings from a bet on to a subsequent wager or series of wagers. 

  • To convert (a situation, thing, etc.) into something better. 

noun
  • A bet or series of bets where the stake and winnings are cumulatively carried forward; an accumulator. 

rack up

verb
  • to gain (points etc.; in a game or sport), to accumulate 

  • to arrange in a rack 

  • to acquire, to gather together. 

  • to defeat severely, to thrash 

How often have the words parlay and rack up occurred in a corpus of books? (source: Google Ngram Viewer )