As Democrats have pushed for a comprehensive overhaul of the country's health system, much of their plans and rhetoric have focused on providing coverage for America's uninsured.
Although that effort stalled following Massachusetts Republican Scott Brown's election to the Senate, President Barack Obama reiterated that imperative in his State of the Union address last month. "By the time I'm finished speaking tonight," Obama said, "more Americans will have lost their health insurance. Millions will lose it this year." He continued, "I will not walk away from these Americans."
Here's a look at who those Americans are.
How many Americans are uninsured?
According to the Census Bureau, in 2008, more than 46 million Americans, about 15 percent of the population, did not have health insurance. Some experts believe the number is now larger because of the recession.
Who are the uninsured?
Low income is a strong factor in identifying the uninsured. About two-thirds of Americans without coverage earn less than twice the federal poverty level, which is $22,050 for a family of four. Almost 25 percent of the uninsured are eligible for Medicaid, the federal-state program to cover the poor, but are not enrolled.
The vast majority of the uninsured - 80 percent - are in working families. And, a higher percentage of minorities are uninsured than whites. Nearly 80 percent are U.S. citizens, and 15 percent are undocumented immigrants.
The uninsured rate for people between the ages of 19 and 29 is 30 percent, the highest rate of any age group. Although many of these young people are working, their wages are often low, and they may find coverage unaffordable.
People whose employers don't offer health benefits may also find more costly individual insurance plans too expensive. For others, prior medical conditions can restrict their access to coverage. And still others, believing that they are in good health and will not need it, opt not to buy insurance.
The uninsured are less healthy than the rest of the population. While about 60 percent report they are in excellent or very good health, 10 percent say they are in poor or fair health. That's twice as many as those with coverage. The Centers for Disease Control and Prevention's latest National Health Interview Survey, released in December, found that 7.2 percent of Americans put off "needed medical care" in the first six months of last year.
Even though the latest Census Bureau figures indicate that more children slipped into poverty in 2008, their uninsured rate dropped from 11 percent in 2007 to 9.9 percent in 2008. The decline reflected the expansion of two government programs: the Children's Health Insurance Program and Medicaid.
Who pays the medical bills of the uninsured?
A 2008 study in the journal Health Affairs estimated that uninsured patients received about $86 billion in care in 2008. Of that amount, $30 billion came out of their pockets, leaving more than $56 billion in uncompensated care: $35 billion for hospitals; nearly $14 billion for community-based providers and close to $8 billion for private physicians.
Some of those uncompensated costs are recouped by hospitals and providers through government programs established to help subsidize care for the poor.
Charities also provide some support, such as funding free clinics. The remainder is shifted to insurers and their customers in the form of higher charges for health care. The Health Affairs study estimated that insurers and customers paid $14.1 billion toward the uninsured, although other groups, including the liberal health advocacy group Families USA, argue that insurers and customers bear even more of the burden.
How could Congressional health overhaul proposals affect the uninsured?
The Democratic proposals passed by the House and Senate - in limbo for now - would require most people to buy coverage. Those earning less than the poverty level, members of Indian tribes and people with religious objections to health insurance are among those who would not have to carry insurance. The House bill would also require many employers to offer coverage, and the Senate version would levy penalties on large employers that choose not to do so.
Both proposals would establish insurance "exchanges" with standardized benefits to enable individuals or businesses to compare and buy plans.
The bills would expand Medicaid coverage to include some people who don't qualify now for various reasons, including their incomes, and would provide subsidies to help people (some earning up to four times the poverty level) buy insurance. At least 9 percent of uninsured Americans make too much money to get subsidies under the bills. And some people who receive subsidies may still find that the total cost of insurance, including co-payments and deductibles, to be either unaffordable or undesirable.
Illegal immigrants would not be eligible for the expanded Medicaid programs and would not receive subsidies. The Senate plan would bar illegal immigrants from buying insurance through the exchanges.
The bills also seek to reduce the number of uninsured by barring private insurers from rejecting applicants who have pre-existing conditions.
Republican proposals would make access more available to uninsured by promoting state-run high-risk pools and health exchanges to help consumers choose affordable plans. The GOP would also allow individuals to buy policies across state lines and provide refundable tax credits to buy insurance.
The CBO estimates that the Senate bill would reduce the number of uninsured by about 31 million, the main GOP plan would reduce the number by about 3 million.
The Census Bureau: Health Insurance Coverage 2008
The Congressional Budget Office analysis of the Republican House plan, Nov. 4, 2009
The Congressional Budget Office analysis of the Senate bill, Dec. 19, 2009
The Janurary-June 2009 National Health Interview Survey
Economic Policy Institute
Families USA: Hidden Health Tax
Health Affairs: Covering The Uninsured In 2008
Kaiser Family Foundation: Side-By-Side Analysis of Major Health Care Reform Proposals
Kaiser Family Foundation: The Uninsured: A Primer"
Kaiser Health News: Caught In The Middle: Making Too Much - And Too Little - To Benefit From Health Care Changes
Urban Institute: How Will the Uninsured be Affected by Health Reform?
This story was produced through collaboration between NPR and Kaiser Health News (KHN), an editorially independent program of the Henry J. Kaiser Family Foundation, a nonpartisan health-care policy research organization. The Kaiser Family Foundation is not affiliated with Kaiser Permanente.