The global economic crisis has reduced the number of billionaires and made the richest people in the world poorer, according to Forbes magazine.

Forbes found 793 billionaires in 2009, down 30% from a year earlier. This is the first decline since 2003.

The total net worth of people on the magazine's list this year fell 46% to $2.4 trillion. The average billionaire is now worth $3 billion, 23% less than in 2008.

Despite losing $18 billion in the past year, Microsoft Corp. co-founder Bill Gates reclaimed the title of richest man in the world, with a total net worth of $40 billion.

Warren Buffett is No. 2, with $37 billion. He lost $25 billion in the past year as shares in his company, Berkshire Hathaway Inc., dropped nearly a third in value.

Mexican telecom titan Carlos Slim Helu, who lost $25 billion, is third, and Oracle Corp. Chief Executive Larry Ellison is No. 4.

The latest list includes citizens of 52 countries and one principality. Americans hold 10 of the top 20 spots, compared with four last year.

New York City Mayor Michael Bloomberg, at No. 17, is the only member of the top 20 whose net worth climbed during the past year. Bloomberg, who makes a salary of $1 a year as mayor, benefited from a re-evaluation of his company, Bloomberg LP. He also bought a 20% stake in his company from cash-strapped Merrill Lynch in July for $4.5 billion.

Thirty-two Russians made Forbes' list, down nearly two-thirds from the 2008 total.

Anil Ambani, who owns Reliance Infrastructure Ltd. -- previously known as Reliance Energy Ltd. -- of India lost the most, $32 billion, this year of any on the list after posting biggest increase last year. He came in at No. 34.

Indian steel magnate Lakshmi Mittal, No. 8, lost $25.7 billion during the past year.

Among the billionaires last year who didn't qualify in 2009: former American International Group Inc. Chief Executive Maurice 'Hank' Greenberg, former Citigroup Inc. Chief Executive Sandy Weill and Facebook founder Mark Zuckerberg.

Kathy Shwiff