Microsoft has gotten a new CEO, bought Nokia's devices and services business, and had better-than-expected earnings the past few months -- another big change is that company chairman Bill Gates has reclaimed his title as the world's richest person.

Forbes released its annual rankings for the world's richest people on Monday showing that Gates overtook telecom mogul Carlos Slim for the first time in four years. Gates' current net worth is $76 billion, up from $67 billion last year, while Slim's fortune fell from $73 billion to $72 billion. The Microsoft chairman has held the No. 1 spot for 15 of the last 20 years.

The world now has 1,645 billionaires, according to Forbes; 172 of them are women and 492 are from the US. About 66 percent of these billionaires created their own fortunes, while 13 percent inherited them and 21 percent have added onto their previous fortunes.

Tech executives make up a good portion of the world's billionaires. Besides Gates, Oracle's Larry Ellison, Google's Larry Page and Sergey Brin, Amazon founder Jeff Bezos, WhatsApp founders Jan Koum and Brian Acton, Dropbox CEO Drew Houston, and many more also made the list this year.

The bigger dollar gainer of all billionaires was Facebook CEO Mark Zuckerberg, whose net worth went from $15.2 billion to $28.5 billion in the last year. This year Facebook COO Sheryl Sandberg and Vice President Jeff Rothschild also made the list for the first time.

Gates has held the richest American title for the last 20 years, and earlier this year Bloomberg pegged the chairman as being slightly ahead of Slim for having the largest fortune worldwide. It appears Gates' net worth hasn't necessarily been made from Microsoft stock, but rather from other financial holdings and private investments.

While Gates has a $76 billion fortune, he has donated more than $28 billion to the Bill & Melinda Gates Foundation, which works on the eradication of polio, malaria, and other dangerous diseases.