Bill Gates remains the richest person in the U.S., just as he was last year, according to Wealth-X, a provider of research on the ultra-wealthy.

The founder of Microsoft is worth $70.8 billion and tops the list of U.S. billionaires.

The next four people on the list, who held the same positions last year, are Warren Buffett with $59.8 billion, Oracle-founder Larry Ellison with $46.4 billion, Kansas businessman David Koch with $41.5 billion, and James Walton of the Wal-Mart family ownership with $37.1 billion.

The 50 wealthiest people in the country are worth a collective total of $540 billion, a 19 percent increase over last year, according to Wealth-X. The average net worth of the individuals on the list is $10.8 billion, a $1.7 billion increase over last year’s average of $9.1 billion