Overall, 47 million people lacked health insurance last year, the Census numbers released Tuesday showed, up from 44.8 million in 2005. The percentage of the U.S. population lacking health insurance last year rose to 15.8%, the highest level since 1998. In 2005, 15.3% were uninsured.

The addition of more than 2 million people to the uninsured comes as Congress and the White House wrangle about whether to expand a program to insure children of low-income families. The Census figures showed the percentage of uninsured children hit 11.7% last year, up from 10.9% in 2005.

The House and Senate are working to reconcile two bills that would expand the program by up to $50 billion over five years so more children could be covered. President Bush has proposed a $5 billion increase over five years and threatened to veto any larger expansion.

Already, many states are moving to enact their own versions of health reform. Some, such as Illinois, have broadened coverage for children and are now looking at expanding government programs to include more adults. Massachusetts passed a law last year requiring everyone to have insurance, and a similar proposal is under debate in California.

Fueling the rise in uninsured in 2006 was a continuing drop in the percentage of people who get their insurance through their jobs. Job-based health insurance, which is the way most people get their coverage, began falling in 2001. The percentage covered by job-based insurance fell to 59.7%, from 60.2% in 2005.

Many jobs, particularly low-wage ones, don't come with insurance. An additional 1.3 million full- or part-time workers were uninsured last year compared with 2005, the Census found.

Reasons for the decline in coverage among workers include fewer employers offering coverage and fewer workers enrolling, even if their employers do provide insurance. Premiums rose 7.7% last year, hitting $11,480 for a typical family plan offered by employers, according to a survey by the Kaiser Family Foundation.

"Workers are struggling with the cost, and they're declining (coverage)," often because the cost of premium increases is rising far faster than wages, says Paul Fronstin, with the Employee Benefit Research Institute, a non-partisan group in Washington.

While low-income households have the highest uninsured rate, the rate rose fastest among those living in households with annual incomes above $75,000, hitting 8.5%, up from 7.7% in 2005.

The Census Bureau also reported:

•19.3% of children in poverty lacked insurance.

•Hispanics had the highest rate of no insurance, with 34.1%, or 15.3 million, uninsured in 2006. The rate for African-Americans increased to 20.5% from 19% in 2005, while the rate for whites was statistically unchanged at 10.8%. The rate among Asians fell to 15.5% from 17.2%.

•Among the foreign-born population, the uninsured rate for naturalized citizens was statistically unchanged at 16.4%, while the uninsured rate for non-citizens increased to 45% from 43.1%.