NEW YORK (AP) _ Four in 10 of the super rich in America made their fortunes the old fashioned way - they inherited them.

The Forbes magazine list of the 400 wealthiest Americans includes 162 people whose fortunes were mostly or entirely inherited. Their average estimated net worth was $580 million.

The list included 214 people who built their fortunes without significant inheritances. Their average estimated net worth was $525 million.

Among the working rich, manufacturing provided fortunes for 84 of the Forbes 400, while media enterprises provided great wealth for 75 others. Seventy-three made fortunes in real estate, 69 from financial operations, 29 from oil and gas, 18 from retailing, 16 from high technology and 16 from agriculture.

Stanford University graduates can take heart - graduates of Stanford on the list had a average estimated net worth of $725 million, highest among all Forbes 400 college graduates. Columbia graduates were second with an average estimated net worth of $635 million, followed by Yale graduates, $620 million; Princeton, $600 million; MIT, $510 million; and Harvard, $400 million.