More than $70bn (£50bn) has been wiped off the wealth of the world's 20 richest people following a slump on global financial markets, according to the latest annual ranking of billionaires by Forbes.

The combined wealth of the top 20 has fallen from $899bn last year to $827bn. The Forbes report also shows that the number of billionaires has fallen from a record 1,826 in 2015 to 1,810.

The list continues to be dominated by men. Out of 1,810 billionaires, just 190 are women, a fall from 197 in 2015.

The biggest loser was Carlos Slim, the Mexican telecoms tycoon, who has seen his fortune drop from $77.1bn to $50bn in a year.

Bill Gates has been crowned the richest man in the world for the third year in a row, although the Microsoft founder's fortune also dipped from $79.2bn to $75bn.

The biggest gainer was Mark Zuckerberg, the boss of Facebook, whose wealth grew by $11.2bn to give him a total net worth of $44.6bn.

Zuckerberg is the sixth richest person in the world, behind Jeff Bezos, the Amazon founder, Slim, investor Warren Buffett, Amancio Ortega, the businessman behind the Zara fashion empire, and Gates.

The only female billionaires in the top 20 inherited their wealth, including Liliane Bettencourt, the heir to the L'Oreal empire, and Alice Walton, daughter of the Walmart founder, Sam Walton.

The richest self-made woman is Zhou Qunfei, who is 205th on the list and valued at $5.9bn. She made her fortune by founding the touchscreen maker Lens Technology.

Across all billionaires, 1,186 are self-made, 228 inherited their wealth and 396 inherited a portion but are growing it. Just 33 of the 190 female billionaires are self-made.

The US remains home to the most billionaires. There are 540 American citizens on the list compared with 536 last year. There are 489 in Europe, with the wealth of the continent's billionaires growing from $1.19 tn to $1.83 tn.

The number and value of billionaires in Asia-Pacific also grew, but the Middle East, Africa and the rest of the Americas took a hit as the value of oil and other commodities fell sharply. The number of billionaires in the Middle East and Africa fell from 106 to 90, while the Americas, not including the US, fell from 140 to 101.

China has the most billionaires after the US, with 251, up on 213 last year. Germany is third with 120 and India is fourth with 84.

The UK has 50 billionaires, down from 53 in 2015. This includes seven newcomers, including theatre producer Cameron Mackintosh and John Bloor, the owner of Triumph Motorcycles.