Moving in to the top 10 for the first time were French entrepreneur Bernard Arnault ($21.5 billion, No. 7), whose luxury Dom Perignon, Fendi and Louis Vuitton brands are no doubt staples for fellow members of the billionaires club -- like Canadian publisher Kenneth Thomson and family ($19.6 billion, No. 9) and Hong Kong businessman Li Ka-shing, whose $5.8 billion increase to $18.8 billion put him at No. 10.
The rest of the top 10 included Mexican telecom heir Carlos Slim Helu (No. 3, $30 billion); Indian steel tycoon Lakshmi Mittal (($23.5 billion, No. 5) and Saudi Arabian investor Prince Alwaleed, the nephew of the Saudi king.
The Walton family, children of legendary Wal-Mart founder Sam Walton, saw their considerable fortune decline this year. The family ranked Nos. 10 through No. 13 on last year's list, ranging from oldest son S. Robson Walton's $18.2 billion to daughter Helen Walton's $18.0 billion. But the past year was not as kind, and the Walton family saw a collective $9.4 billion drop in net worth push them to Nos. 17 to 20 on the 2006 list. The death of Sam Walton's son, John, in a plane crash also pushed daughter-in-law Christy into the No. 17 spot.
Other Americans in the top 20 included software developer Michael Dell of Dell Computers ($17.1 billion, No. 12), and Las Vegas casino mogul Sheldon Adelson ($16. 1 billion, No. 14).
Cosmetics heiress Liliane Bettencourt, daughter of L'Oréal founder Eugene Schueller, ranked as the richest woman in the world. Her net worth of $16 billion places her at No. 15.