COMPUTER magnate Bill Gates's net worth rose to $79.2 billion (£51.5bn) in 2015 from $76bn (£49.4bn) last year according to US magazine Forbes. It puts him at the top of the magazine's list of the world's billionaires for the second consecutive year. The co-founder of Microsoft has topped the list for 16 of the last 21 years. In second place is telecom mogul Carlos Slim Helu, with a net worth of $77.1bn (£50.1bn). He had topped the list in 2013. Next is investor Warren Buffett, who moved up one slot this year with a net worth of $72.7bn (£47.2bn). Forbes said there were 1,826 billionaires on its list this year, up from 1,645.