The percentage of Americans struggling below the poverty line in 2009 was the highest it has been in 15 years, the Census Bureau reported Thursday, and interviews with poverty experts and aid groups said the increase appeared to be continuing this year.

With the country in its worst economic crisis since the Great Depression, four million additional Americans found themselves in poverty in 2009, with the total reaching 44 million, or one in seven residents. Millions more were surviving only because of expanded unemployment insurance and other assistance.

And the numbers could have climbed higher: One way embattled Americans have gotten by is sharing homes with siblings, parents or even nonrelatives, sometimes resulting in overused couches and frayed nerves but holding down the rise in the national poverty rate, according to the report.

The share of residents in poverty climbed to 14.3 percent in 2009, the highest level recorded since 1994. The rise was steepest for children, with one in five affected, the bureau said.