In 1949, the total value of listings on the New York Stock Exchange was $150 billion. In 1984, the total value of all US public equities was $2,000 billion. In 2005, the total value of Big Board listings was $20,000 billion, plus $3,000 billion listed on NASDAQ.
Then, from Oct 2007 – Oct 2008, US stock market capitalisation lost $7,000 billion.
various sources including several versions of The Intelligent Investor