Gates Back on Top of Forbes' Billionaire Rankings

Microsoft co-founder Bill Gates is once again the world's richest person.

Forbes magazine announced its ranking of the world's billionaires Monday. Gates, who led the list for 15 of the past 20 years, won the spot back from Mexican telecom mogul Carlos Slim Helu, who had topped the list for the past four years. Gates' net worth is estimated at $76 billion; Slim Helu follows at $72 billion.

Spanish clothing magnate Amancio Ortega, known for the Zara retail chain, maintained his No. 3 spot and came out ahead of famed U.S. investor Warren Buffett, who ranked fourth. Larry Ellison of Oracle came in fifth.

Forbes says a record 1,645 billionaires made the list this year, with an average net worth of $4.7 billion. That's up from 1,426 billionaires last year with a net worth of $4.2 billion. Total net worth of this year's list was $6.4 trillion, up from $5.4 trillion last year.

The magazine said that 1,080 of the billionaires were self-made, 207 inherited their wealth and 352 inherited a portion but are still growing it.

The largest net worth gainer on the list was Facebook's Mark Zuckerberg, who more than doubled his fortune to $28.5 billion as the value of his company's stock soared. He ranks 21st on the list.

The social media giant helped bring a few notable newcomers to the list, including Facebook's Chief Operating Officer Sheryl Sandberg and WhatsApp founders Jan Koum and Brian Acton, who recently sold their business to Facebook for $19 billion.

Forbes said 268 billionaires were new to the list, beating out a prior high of 226 newcomers in 2008. And a record number of women made the list this year, with 172 women joining, up 25 percent from last year.

Altogether 100 people dropped out of the rankings, while 16 passed away.

The U.S. was the country with the greatest number of billionaires at 492, followed by China with 152 and Russia with 111. Billionaires from four new countries joined, adding Algeria, Lithuania, Tanzania and Uganda to the geographic mix.