691 people from 47 countries with a combined fortune of $2.2 trillion feature in the annual Forbes magazine list of the richest people in the world. Bill Gates ($46.5BN) heads the list, as he has done for over a decade. Microsoft cofounder Paul Allen ($21BN) is still in the top ten, in a list that introduced 131 new billionaires including Martha Stewart ($1BN).

Google founders Sergey Brin and Larry Page, at 31 and 32 years of age, are two of only 29 billionaires under 40. Last year they were 552nd on the list, with $1BN apiece, but this year they moved up to no. 55 with $7.2BN.

Microsoft cofounder Paul Allen is still in the top ten, in a list that introduced 131 new billionaires including Martha Stewart.

In its accompanying editorial, Forbes magazine noted that the U.S. "is now home to an astonishing 341 billionaires, just shy of half the world's billionaire population."

"Bill Gates keeps his throne for another year," the Forbes editorial continued, "but with Microsoft stock flat-lining, his days as the world's richest man may be numbered."

Somehow it doesn't seem likely that anyone will be betting on it though. Not even Larry Ellison ($18.4BN) or Michael Dell ($16BN).