WASHINGTON (AP) ― The Newseum has become a major attraction with 4 million people visiting its exhibits about journalism and freedom of speech. Yet, in five years since moving to its new home overlooking the U.S. Capitol, it’s been struggling mightily to cover its costs.

Public financial documents reviewed by the Associated Press show revenue fell short of expenses by millions of dollars in 2009, 2010 and 2011. Its parent organization, the Freedom Forum, has used its endowment to provide the bulk of the Newseum’s operating revenue since its creation, and the endowment’s principal value has steadily declined from $600 million to about $373 million at the end of 2011.

Nonprofit management consultants say it’s worrisome for a museum to be relying so heavily on a shrinking endowment, but the Newseum’s top executive says it’s not in financial trouble.

To rein in costs, the Newseum imposed four rounds of staff layoffs since 2008, most recently in January, and slashed employee retirement contributions. The Newseum is also reorganizing its educational programs under a separate nonprofit organization. Meanwhile, compensation for its chief executives struck some experts as overly generous.

“We’ve certainly worked on tightening up on expenditures. We certainly are going to be working on additional fundraising initiatives,’’ President and CEO James Duff said in an interview. “I think we’re making good progress. And certainly our numbers are very, very encouraging.’’

The Newseum is Washington’s most expensive museum, charging $22 for adults and $13 for youth, though many other attractions are able to offer free admission because they’re taxpayer-funded.

It has drawn more visitors each year since it moved to its current location, including 817,000 in 2012. A spokesman said its visitor count is expected to grow again by 5 to 10 percent this year.