From washingtonpost.com:

Twenty-eight percent of the public is aware that nearly 4,000 U.S. personnel have died in Iraq over the past five years, while nearly half thinks the death tally is 3,000 or fewer and 23 percent think it is higher, according to an opinion survey released yesterday.

The survey, by the Pew Research Center for the People and the Press, found that public awareness of developments in the Iraq war has dropped precipitously since last summer, as the news media have paid less attention to the conflict. In earlier surveys, about half of those asked about the death tally responded correctly.