Each year, Forbes magazine compiles a list of the 400 richest Americans. As of September 17, 2008,

Question:

Each year, Forbes magazine compiles a list of the 400 richest Americans. As of September 17, 2008, the top 10 on the list are as shown in the following table.
Person Wealth ($ billions)
William Gates III ............57.0
Warren Buffett .............50.0
Lawrence Ellison ............27.0
Jim Walton ...............23.4
S. Robson Walton ............23.3
Alice Walton ..............23.2
Christy Walton & family ..........23.2
Michael Bloomberg ............20.0
Charles Koch .............19.0
David Koch ...............19.0