NEW YORK (AP) - Oprah Winfrey is a little richer, but other billionaires have gotten a lot richer over the past year, so she's dropped in the Forbes list of the 400 richest Americans. Oprah is now worth $2.9 billion, $200 million more than last year. She's in 184th place, down from 151 the year before. George Lucas is nearly $1 billion richer than last year. He's at number 109 with $4.2 billion. That's nearly $1 billion more than his friend Steven Spielberg, who's in 151st place. Bill Gates is the richest person in the country for the 20th straight year. He's worth $72 billion.