A new USA TODAY/Gallup Poll found few Americans plan to observe the upcoming 9/11 anniversary in a formal way, though the majority still regards the terror attack as the most memorable event in their lifetime.

The poll, released in Washington on Monday, found 71 percent of Americans called 9/11 the most memorable news event of their lifetime.

Asked whether 9/11 changed the way they live, 29 percent said yes -- up from 18 percent five years ago.

However, only 6 percent said they would observe Tuesday's anniversary in a formal way, such as attending a memorial event or taking the day off.

Most of them, 71 percent, -- said they would mark it informally, perhaps by praying, keeping a moment of silence or watching news coverage.

Almost one-quarter said they didn't plan to observe it at all.

Edward Linenthal, a University of Indiana scholar who has written about memorials in US history, says a certain loss of focus is inevitable on "the in-between anniversaries" whose years don't end in 5 or 0.

"Like any event, even Pearl Harbor, the more time goes by, the less central it becomes to our experience," says Robert Thompson, a Syracuse University professor who studies US popular culture.

(Xinhua News Agency September 11, 2007)