a step up the ladder vs preferment

a step up the ladder

preferment

noun
  • Prior claim (on payment, or on purchasing something); the first rights to obtain a particular payment or product. 

  • Advancement to a higher position or office; promotion. 

  • A position (especially in the Church of England) that provides profit or prestige. 

  • A mixture of flour, water and yeast that is allowed to ferment prior to another baking process 

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