Bill Gates: The Rich Got Richer in 2013 Gus Ruelas / Reuters Bill Gates at the Milken Institute Global Conference in Beverly Hills, Calif., May 1, 2013. If you happen to be one of the wealthiest people on earth, chances are you can look back on 2013 as a year of financial success. The total net worth of the world's 300 richest individuals rose $524 billion in 2013, according to the Bloomberg Billionaires Index. Only 70 of the 300 posted a net loss for the year. As the ball dropped on New Year's Eve, the aggregate net worth of the world's top billionaires was $3.7 trillion. Microsoft founder Bill Gates, 58, had the best year, with his fortune increasing by $15.8 billion to $78.5 billion. Earlier in 2013, Gates knocked off Mexican investor Carlos Slim to retake the title of the world's richest person. The next-biggest winner for the year was gaming mogul Sheldon Adelson, 80, whose fortunes improved to the tune of $14.4 billion. "The rich will keep getting richer in 2014," real estate and energy magnate John Catsimatidis told Bloomberg. Interest rates will remain low, equity markets will keep rising, and the economy will grow at less than 2 percent. Income inequality in the U.S. has been rising for decades and is now at a level unseen since 1928. The poverty rate in America held steady at 15 percent in 2012, the most recent year for which the Census Bureau has released data, though the total number of those living in poverty ticked up to 46.5 million. Nearly one in four Americans under age 18 lives below the poverty line. Bloomberg