The number of people in the United States without health insurance rose by more than 2 million in 2006, including about 700,000 million children, according to data released Tuesday by the U.S. Census Bureau.

A total of 47 million people were without insurance coverage last year, the Census Bureau said, up from 44.8 million in 2005.

The increase represents a one-half of 1 percent increase of Americans living without health coverage, to 15.8 percent. That is the highest percentage since 1998, when the rate was also 15.8 percent after a decade of increasing numbers. According to the Census Bureau, there were 8.7 million uninsured children in 2006, up from 8 million the previous year.

With Congress preparing for a conference on legislation to greatly expand the State Children’s Health Insurance Program, or SCHIP, the news is expected to figure prominently in the debate.

Democrats quickly pounced on the numbers as justification for boosting SCHIP’s funding. “The new Census report illustrates why Congress needs to immediately pass legislation to strengthen ... SCHIP to ensure that more of America’s children have health insurance,” House Speaker Nancy Pelosi, D-Calif., said in a statement.

The House and Senate are expected name conferees shortly after lawmakers return next week from the August recess. Supporters of the House bill (HR 3162), which would expand SCHIP by nearly $50 billion, said it would provide coverage for an additional 7.5 million uninsured children and adults. The Senate measure (HR 976) would increase SCHIP by $35 billion, accounting for 6.1 million more people enrolled, its backers say.

While both proposals promise to take a substantial bite out of the number of uninsured number, each would leave some 40 million Americans without coverage.

President Bush has promised to veto both versions.

The census figures paint a picture of the uninsured as poor or lower-middle class, young and employed. They show 62 percent live in households making less than $50,000 per year; of that 62 percent, more than half are in households making from $25,000 to $50,000. Many incomes were higher: 18.1 percent of the uninsured came from households making $50,000 to $74,999.

Many of the uninsured had jobs, as well: 58.7 percent of the uninsured worked either full- or part-time during 2006.

Young adults made up the largest portion of the uninsured. Ages 18 to 34 comprised 40.4 percent of those without coverage.

In addition, 73.2 percent of the uninsured were U.S. citizens; foreign-born residents were more likely to be uninsured despite their smaller total numbers.