Forbes has released its annual list of billionaires for this year. Microsoft Corporation (NASDAQ:MSFT) founder Bill Gates has replaced Mexican telecom titan Carlos Slim Helu as the world’s richest man. In total, 1,645 billionaires are featured on the list. Their aggregate net worth rose from $5.4 trillion last year to $6.4 trillion.

A booming tech industry helped propel fortunes. Facebook Inc (NASDAQ:FB), whose stock has more than doubled over the last 12 months, has created numerous billionaires. Mark Zuckerberg’s fortune increased from $13.3 billion to $28.5 billion. Facebook COO Sheryl Sandberg joined the list of billionaires for the first time, along with the social networking giant’s VP Jeff Rothschild. Thanks to Facebook’s recent $19 billion acquisition, WhatsApp founders Brian Acton and Jan Koum also joined the list. There are 26 new tech billionaires, and 10 of them are American including Workday founder Aneel Bhusri and Dropbox CEO Drew Houston.

The United States once again showed that it has the most number of billionaires by some distance. There are 492 U.S. billionaires, 152 Chinese billionaires, and 111 Russian billionaires on the list. More importantly, wealth is spreading rapidly to new places. Billionaires from Uganda, Algeria, Tanzania and Lithuania joined the billionaires’ club for the first time. And it was the first time an African broke into the top 25. Aliko Dangote of Nigeria with a net worth of $25 billion is 23rd richest person in the world.

The interesting fact is that more than two-third billionaires have built their own fortunes. Only 13% have inherited their wealth, and another 21% have been adding to the wealth they received. This year, 16 billionaires passed away, while another 100 dropped out of the ranks. Let’s have a look at the ten richest billionaires on the planet, and how they amassed their wealth.

10 World’s Richest People

#10: Jim Walton

Jim Walton

An heir to Wal-Mart Stores, Inc. (NYSE:WMT) fortune, Jim Walton’s net worth increased by $8 billion since last year to $34.7 billion. He jumped four spots on the Forbes list to occupy 10th place. Jim Walton is the chairman and chief executive of Arvest Bank.

#9: Christy Walton & family

Christy Walton

Christy inherited the fortunes of her husband John Walton when he passed away in 2005. John Walton was the son of Wal-Mart Stores, Inc. (NYSE:WMT) founder Sam Walton. Christy jumped two spots on the billionaires’ list as her net worth increased by $8.5 million to $36.7 billion.

#8: Sheldon Adelson

Sheldon Adelson

The chief of Las Vegas Sands Corp. (NYSE:LVS) has a net worth of $38 billion. He jumped seven spots on the list. The casino tycoon’s wealth was almost ruined during the 2009 financial crisis when shares of Las Vegas Sands fell to as low as $1.77 apiece. Many began to argue that Adelson was on the verge of bankruptcy, but the wise old man never gave up. He continued to expand his business in Asia. Today, Las Vegas Sands shares have surged to $85.97.

#6 (tie): David Koch

David Koch

David Koch is the co-owner of one of the world’s biggest privately-held businesses in the world, Koch Industries. Though his fortune is up $6 billion from last year, there is no change in his position.

#6 (tie): Charles Koch

Charles Koch

Along with his brother David Koch, Charles is the co-owner and executive vice president of Koch Industries. The two brothers have the same net worth of $40 billion each.

#5: Larry Ellison

Larry Ellison

The flamboyant founder and CEO of Oracle Corporation (NYSE:ORCL) has a net worth of $48 billion. Harvard Business School named him the Entrepreneur of the Year in 1990, though he didn’t graduate from college. Ellison was the fifth richest man last year as well.

#4: Warren Buffett

warren buffett Mr Buffett the Teacher Executives

The world’s most successful investor and chairman of Berkshire Hathaway Inc. (NYSE:BRK.A) (NYSE:BRK.B) is the fourth richest man in the world. He has a net worth of $58.2 billion. Buffett is a well-known philanthropist, and he has signed the Giving Pledge.

#3: Amancio Ortega

Amancio Ortega

Ortega avoids media attention. He is the former chairman of Inditex, a Spanish retail giant whose holdings include fashion brand Zara. Ortega has a fortune of $64 billion, and there is no change in his position on the Forbes list from last year.

#2: Carlos Slim Helu

Carlos Slim Helu

Slim’s professional life is one of the best rags-to-riches stories. Today, the Mexican telecom mogul has a net worth of $72 billion. But he comes from a humble beginning. Carlos’ father was an immigrant shopkeeper. Though he is the second richest man today, his close friends say that Slim still wears inexpensive suits and prefers old-style pen and paper.

#1: Bill Gates

bill gates richest people

Microsoft Corporation (NASDAQ:MSFT) founder has topped the Forbes list 15 of the last 20 years. The Harvard dropout now devotes much of his time to charity. Bill Gates has donated billions of dollars through his Bill and Melinda Gates Foundation. Mr. Gates’ wealth swelled as shares of Microsoft gained 35% over the past 12 months.