Do YOU know the answer to that?
Let me guess?
Maybe 1% of them
Twenty Billionaires Who Started With Nothing
While most of the world's richest people earned their money, some had farther to climb.
Sheldon Adelson: son of a cab driver... At the end of 2006, The Times has estimated, Adelson's net worth had grown by about $1 million an hour for two straight years.
Carl Berg: father died when he was 10, schoolteacher mother raised him... Today, Berg is chairman and chief executive of Cupertino (Calif.)-based Mission West Properties (MSW), a giant real estate investment trust.
Stephen Bisciotti: father died at 8, raised with two siblings by single mother... bought the Baltimore Ravens National Football League team in 2004.
Leon Charney: Child of immigrant parents, destitute after father died... started law firm with $200, eventually made more than a billion dollars from real estate investments, especially in properties around Manhattan's Times Square.
I could continue, but you get the idea.