equality vs preference

equality

noun
  • The equal treatment of people irrespective of social or cultural differences. 

  • The fact of being equal, of having the same value. 

  • The fact of being equal. 

preference

verb
  • To give preferential treatment to; to give a preference to. 

noun
  • The option to so select, and the one selected. 

  • The selection of one thing or person over others (with the main adposition being "for" in relation to the thing or person, but possibly also "of") 

  • The state of being preferred over others. 

  • Preferans, a card game, principally played in Eastern Europe. 

  • A strong liking or personal valuation. 

  • A preferential bias; partiality; discrimination. 

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