The number 13 has long been considered unlucky by superstitious people around the globe. How fitting, then, that Bill Gates' reign as the world's richest person ends after his 13th year at the top.

Despite being worth $58 billion, $2 billion more than last year, Gates is now just the world's third-richest person, ceding the top spot ranking to his good friend and partner in philanthropy, Warren Buffett, whose net worth jumped $10 billion to $62 billion.  (All stock prices and net worth valuations were locked in on Feb. 11.)  Ranked No. 2 is Mexican telecom tycoon Carlos Slim Helu, whose fortune has doubled in just two years to $60 billion.

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The world's billionaires
Celebrity billionaires            

It is certainly a dawning of a new era. But not just because of Gates' fall. The 22nd annual rankings of the World's Billionaires reflects all sorts of upheavals in the list's makeup. Two years ago, half of the world's 20 richest were from the US. Now only four are. India wins bragging rights for having four among the top 10, more than any other country.

For the first time ever, the number of billionaires Forbes could identify crossed into four figures, reaching 1,125. The total net worth of the group is $4.4 trillion, up $900 billion from last year. Despite the turbulence in the US markets, Americans account for 42 per cent of the world's billionaires and 37 per cent, of the total wealth; those shares are down two and three percentage points, respectively, from last year.

Sixteen years after the collapse of the Soviet Union, Russia, with 87 billionaires, is the new No. 2 country behind the US, easily overtaking Germany, with 59 billionaires, which held the honour for six years.

The rankings include 226 newcomers. Seventy-seven of the new faces come from the US, half of whom made their fortunes in finance and investments, including John Paulson and Philip Falcone, both of whom became wealthy shorting subprime debt.

Another third of the new billionaires comes from Russia (35), China (28) and India (19). Two of the most noteworthy new entrants are South Africa's Patrice Motsepe and Nigeria's Aliko Dangote, the first black Africans to make their debut among the world's richest. Dangote is also the first-ever Nigerian billionaire.

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Billionaire bachelors

It is also a record-breaking year for young billionaires, with Forbes finding 50 under the age of 40, 25 of whom are new to the list. Sixty-eight per cent of these under-age-40 tycoons built their 10-figure fortunes from scratch, including Google co-founders Sergey Brin and Larry Page; former Enron trader John Arnold, who now runs a hedge fund; India's Sameer Gehlaut, who started online brokerage Indiabulls [Get Quote]; and, last but not least, Facebook founder Mark Zuckerberg, who at age 23 might just be the youngest self-made billionaire in history.

Zuckerberg is probably destined to be the most talked about newcomer of the year because of his age and ingenious social-networking site, but there are fascinating entrepreneurs of all ages climbing into the ranks.

Some of the more notable ones include China's Gao Dekang, who is one of the world's biggest makers of down jackets and vests; Portugal's Americo Amorim, who turned his grandfather's small cork operation into the world's largest; and Brazil's Eike Batista, who built and lost a gold mining fortune, before hitting it big in iron ore. He is now the world's richest mining billionaire.

With all the rosy news of the past year and the overall gains, it is easy to lose sight of the volatility that has been wreaking havoc on these fortunes on a daily basis for months. For instance, Hong Kong's richest person, Li Ka-shing, lost $5.5 billion of his net worth, all tied to publicly held stocks, in the 37 days between Jan. 4 and Feb. 11.

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Self-made billionaires

Meanwhile, mainland China's richest person, 26-year-old Yang Huiyan, fell from $17.3 billion in September to $7.4 billion in the rankings. Google co-founder Sergey Brin's fortune touched $25.5 billion in the past year but is now down to $18.7 billion.

Others were hit much harder, falling off the list entirely, including Lehman Brothers chief Richard Fuld and Bear Stearns ex-chief James Cayne (he was sacked), both victims of the world's credit crunch, and Pulte Homes' William Pulte, whose stock collapsed along with the housing market.

What will happen in the next 12 months as we continue our wealth watching? There will likely be some big losers, some big winners and a lot of ups and downs in between. The only certainty is change itself.