This year Forbes magazine has named Bill Gates the richest man in the world (again) on its annual billionaires list.

"Bill gates is back on top after a four-year hiatus, reclaiming the title of world's richest person from telecom mogul Carlos Slim Helu of Mexico, who ranked No.1 for the past four years," Forbes wrote.

Gates, who stepped down as board chairman of the Microsoft Corporation in February, saw his wealth grow $9 billion over the past year. Gates has topped Forbes billionaire list 15 times over the past two decades, the magazine said.

The U.S. had the most billionaires at 492. A technology boom and strong stock market helped the U.S. top the list, followed by China with 152 billionaires and 111 in Russia, Forbes reported. Also, the world has the highest number of women billionaires ever seen. There were 42 new women billionaires, increasing the number in that category from 138 in 2013, to 172.

What would a billionaire list be without Facebook founder Mark Zuckerberg, who was the world's biggest dollar gainer. Zuckerberg's wealth is $28.5 billion, up $15.2 billion from last year, Forbes reported. Other technology moguls on the list include WhatsApp founders Jan Koum and Brian Acton, and Dropbox CEO Drew Houston.

Forbes, which has published its rich list for the past 28 years, found billionaires in countries that never made the list. First time billionaires were found in Tanzania, Uganda, Algeria and Lithuania. Nigeria's Aliko Dangote, worth $25 billion, was the first African to make the list's top 25.

Other countries dropped out of the list. Indonesia lost 8 billionaires, possibly linked to its currency falling 20 percent against the dollar, Forbes reported. Turkey, which also had a decline in currency value, lost 19 billionaires.