New York, Mar 12 : Forbes magazine study has revealed that Microsoft Corporation co-founder Bill Gates has reclaimed the title of the richest man in the world, with a total net worth of 40 billion dollars.

According to Fox News, the magazine found 793 billionaires in 2009, which was down by 30 percent from a year earlier.

Apparently, this is the first decline since 2003.

The total net worth of people on the Forbes's list in 2009 fell by 46 percent to 2.4 trillion dollars. The average billionaire's worth is now at 3 billion dollars, 23 percent less than in 2008.

Berkshire Hathaway Inc.'s Warren Buffett was second on the list with a net worth of 37 billion dollars. He lost 25 billion dollars in the past year as shares in his company dropped nearly a third in value.

Mexican telecom titan Carlos Slim Helu, who lost 25 billion dollars, is third, and Oracle Corporation Chief Executive Larry Ellison is on number four.

New York City Mayor Michael Bloomberg, founder of Bloomberg L P, a financial software services company is at number seventeen. He is the only member of the top 20 whose net worth climbed during the past year.

The latest Forbes list has considered citizens of 52 countries and one principality.mericans hold 10 of the top 20 spots, compared with four last year.

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