Americans made more than 4 million requests to the federal government under the Freedom of Information Act in 2004, a new high for requests in a single year, according to a new review by The Associated Press.

"Four million requests in a year is pretty impressive, and it shows that the Freedom of Information Act is a vibrant and important tool," said Harry Hammitt, who publishes Access Reports, a newsletter on freedom of information laws.

But because as many as 80 percent of last year's requests were routine queries for family, personal or medical records, Hammitt cautioned that the public should not assume they led to the release of the historic, political or declassified files people often associate with FOIA.

Requests last year increased from 3.26 million in 2003, according to a survey of reports from more than 70 federal agencies and departments. Most of the increase was due to the 1.5 million requests received by the Social Security Administration, which reported twice as many requests in 2004 than in 2003. Social Security officials said Wednesday that most of those requests were people seeking genealogical information.

"The majority of our requests are for family members who are tracing their family tree," SSA spokesman Mark Hinkle said.

The Internet has sparked a national interest in genealogy, and many Web sites point amateur family historians to the SSA for details about their relatives' names and birth dates.

The Department of Veterans Affairs, in a continued trend, received the most requests - 1.8 million. Most of these involve military medical and personnel records.

Total requests have been steadily increasing since 1998 when standardized record keeping made it possible to figure out such totals. At the same time, many federal departments have been reducing the amount of information they release to the public, an AP review conducted earlier this month found.

"It's a good thing that citizens are using this law for a variety of useful purposes, but we're concerned that the administration is not putting a premium on getting them their answers," said Celia Wexler, Common Cause's vice president for advocacy.

The Freedom of Information Act, passed in 1966, requires the government to release its information to the public, with exceptions for such things as criminal investigations.

This week marks the first-ever national "Sunshine Week," a campaign for government openness spearheaded by journalism groups, universities, the American Library Association and more than 50 media companies, including the AP.

Most federal departments said they received tens of thousands of FOIA requests last year - the Department of Health and Human Services received 225,006, the Department of Homeland Security received 168,882, and the Justice Department received 57,346.

The agencies reporting the fewest requests included the Library of Congress' copyright office, the Office of Government Ethics and the Federal Retirement Thrift Investment Board, all of which received fewer than 100 requests.

On the Net: Sunshine Week: http://www.sunshineweek.org/

AP investigative researcher Randy Herschaft contributed to this report.