Microsoft co-founder and chairman Bill Gates, 45, may not be as rich as he was last year at this time — in this market, who is? — but he still retained the title of richest person in America (and arguably the world), according to the annual survey by Forbes Magazine of the 400 wealthiest Americans. Gates’s bank account reportedly contains $54 billion, down from last year’s $63 billion. Forbes released its findings on its Web site Thursday night. In other rankings, investor Warren Buffett, 71, moved into second place ($33.2 billion), followed by the other Microsoft co-founder, Paul Allen. Oracle chief executive Larry Ellison dropped from the second to fourth perch. The remainder of the top 10, except for Microsoft CEO Steve Ballmer, consisted of relatives of deceased Wal-Mart founder Sam Walton. The combined net worth of all 400 fell from $1.2 trillion in 2000 to $946 billion this year, only the third time there’s been a drop since Forbes began compiling the list in 1982. The list’s average financial heavyweight is worth $2.4 billion, down $600 million from last year. Also worth noting, especially to budding billionaires: 149 of the 400 inherited some or all of their wealth, while the rest made their money themselves; 279 are college graduates, with an average net worth of $2.2 billion; 18 (including Gates, a Harvard dropout) never completed college and have an average net worth of $1.9 billion. And the richest state of all? California, with 92 tycoons, of the 400 on the list. New York City alone has 38.