a vast sum vs big money

a vast sum

big money

noun
  • Large corporations, the people who run them, or corporate interest generally, seen as exerting political influence and prioritising profits over other political concerns. 

  • A large amount of money, especially a significant source of revenue or income. 

adj
  • Involving or transacting a large amount of money. 

How often have the words a vast sum and big money occurred in a corpus of books? (source: Google Ngram Viewer )