Microsoft founder Bill Gates stands atop annual list of the world's richest people for 2016, as Forbes magazine announced its ranking of the world's billionaires on Thursday.

Gates' net worth stood at $75 billion compared to $79.2 billion a year earlier, putting the Microsoft Corp co-founder at the top for the 17th year in the last 22.

Amancio Ortega, the Spanish founder of Inditex SA, which includes clothing retailer Zara, was second at $67 billion, while Berkshire Hathaway Inc chief Warren Buffett was third, at $60.8 billion.

Mexico telecommunications mogul Carlos Slim Helu ranked fourth, worth $50 billion.

Facebook Inc's Mark Zuckerberg, 31, rose to sixth place from 16th last year, as his net worth grew to $44.6 billion.

France's Liliane Bettencourt, who got much of her wealth from cosmetics company L'Oreal SA, was 11th at $36.1 billion.

It is the 30th annual list released by Forbes and features 1,810 billionaires around the world with a total net worth of almost $6.5 trillion.

This year marked the first time the average net worth of a billionaire dropped — to $3.6 billion, down $300 million from last year. The US has 540 billionaires, more than any other country.