bribery vs slush fund

bribery

noun
  • the making of illegal payment, or bribes, to persons in official positions as a means of influencing their decisions 

  • the activity of giving, offering or accepting bribes 

slush fund

noun
  • Money stored for illegal or dishonest purposes. 

  • Money that has not been hypothecated or dedicated to a particular purpose, or which is used for a different purpose than originally intended. 

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