Here's a list of Forbes 2015 ranking of richest people around the globe: 

Billionaire	Net Worth (US dollars)	Nationality
Bill Gates	81.1 billion	American
Carlos Slim Helu	75.1 billion	Mexican
Warren Buffett	73.8 billion	American
Amancio Ortega	65.6 billion	Spanish
Larry Ellison	56.2 billion	American
Charles Koch	43.2 billion	American
David Koch	42.9 billion	American
Christy Walton	41.7 billion	American
Jim Walton	40.6 billion	American
Liliane Bettencourt	40.1 billion	French