WASHINGTON • Despite the economic downturn, the rate of homelessness across the United States decreased 1 percent from 2009 to 2011, according to a report that the National Alliance to End Homelessness released earlier this week.

But at a news conference Wednesday in Washington to discuss the report, officials who advocate for the homeless said they were still concerned about the future, as the slashing of the government's budget has resulted in a decline in federal dollars for the poor.

"This is just the beginning of another year of people sinking deeper and deeper into poverty," Rep. Gwen Moore, D-Wis., said Wednesday at the National Press Club. Moore has sponsored legislation to reauthorize a federal assistance program to fight homelessness.

In these tough economic times, housing has become too expensive for many, said Pete Witte, a National Alliance to End Homelessness research associate. Nearly 6.2 million Americans spent more than 50 percent of their incomes to pay rent in 2010, according to the State of Homelessness in America 2012 report.

The alliance used data from the U.S. Departments of Housing and Urban Development, Health and Human Services, Justice, Labor and Commerce, and from the private real estate group RealtyTrac. It may not be exact, said Nan Roman, the alliance's president and chief executive officer, as it relied on community counts.

In 2011, about 636,017 people lived without permanent homes, down from 643,067 in 2009, according to HUD, although homelessness increased in 24 states and the District of Columbia.

The study says that housing assistance programs that contributed to last year's overall decline in homelessness should be used as a blueprint for coming years.

"The homeless system has been proactive in figuring out what works better and adopting that," Roman said.

The Homelessness Prevention and Rapid Re-Housing Program, a $1.5 billion federal response to the recession, provided an innovative approach to helping Americans get back on their feet, she said. The program provides counseling services and money to eligible participants to prevent homelessness or help them find permanent homes quickly.

While grant money for the program runs out next fall, Roman said the needs of the most vulnerable should be a high priority and Congress should continue to couple permanent housing with supportive services.

As unemployment remained high from 2009 to 2011, families were more likely to "double up," Roman said.