By the numbers

Protesters against the Affordable Care Act rally outside the Supreme Court in Washington before the justices issue their ruling Thursday, June 28.

Reporters and camera crews begin gathering early Thursday outside the Supreme Court in anticipation of the court's expected health care ruling.

President Barack Obama signs the health care legislation in a March 23, 2010, ceremony with Democrats in the White House East Room. The law, which critics dubbed Obamacare, is Obama's signature legislation.

The constitutionality of the 2,409-page act has been challenged by 26 states. The most controversial aspect of the law would require individuals not covered by insurance via their employer or the government to purchase and maintain minimal health insurance or pay a penalty.

The Supreme Court held three days of politically charged hearings in March on the Affordable Care Act.

Opponents of Obama's health care legislation protest in front of the Supreme Court on March 28. Some critics say they believe the Constitution's Commerce Clause does not give government the authority to force Americans to purchase a commercial product such as health insurance.

Advocates for universal, government-financed health care carry signs one month before the health care overhaul was signed into law.

Two years after Obama signed the health care legislation, the Supreme Court took up the historic test of whether it's constitutional.

The Rev. Patrick Mahoney leads demonstrators in prayer outside the Supreme Court on Monday, June 25, as they await the court's ruling.

What the Supreme Court justices decide will have an immediate and long-term impact on all Americans, both in how they get medicine and health care.

• 49.9 million -- The number of uninsured Americans in 2010
• 15.4% - The percentage of children living in poverty who are also uninsured
• 95 million -- Number of people in the U.S. covered by government health insurance

(CNN) -- The Supreme Court is set to rule on the constitutionality of the Patient Protection and Affordable Care Act on Thursday. The landmark decision will dictate the way health care is administered to millions of Americans.

Here's a look at health care in the United States by the numbers, including the populations that could be most affected by the decision on what has come to be known as "Obamacare."

Supreme Court decision on polarizing health care law looms

49.9 million -- The number of uninsured Americans in 2010. That's 16.3% of the total population.

18.4% -- Percentage of uninsured Americans younger than 65 in 2010.

28.4% -- The percentage of Americans 25 to 34 without insurance.

7.3 million -- The number of children in the U.S. without health insurance, 9.8% of all children in the country.

How SCOTUS rulings could shape 2012 race

Supreme Court nears health care ruling

Looking at Romney's health care record.

Health care law in grave trouble?

15.4% - The percentage of children living in poverty who are also uninsured.

All sides preparing for political fallout from health care decision

26.9% -- Percentage of people earning less than $25,000 a year who are also uninsured.

256.2 million -- The number of Americans who were insured in 2010.

195.9 million -- The number of Americans with private health insurance in 2010, 64% of the total population.

What to know about health care

169.3 million -- The number of Americans who get their insurance through the workplace.

95 million -- Number of people in the U.S. covered by government health insurance, 31% of the population.

44.3 million -- Number of Americans receiving Medicare coverage in 2010.

48.6 million -- The number of Americans covered by Medicaid in 2010.

$940 billion -- The amount of money that the Congressional Budget Office estimates it will cost to provide the expanded insurance coverage over 10 years.

House GOP leaders prepare for health care decision

$143 billion -- The amount by which the plan could reduce the deficit over the first 10 years. And over the following decade, the CBO projected, health reform could reduce the deficit by more than $1 trillion, although the agency stressed that such long-term projections are highly uncertain.

2.35% -- The tax rate high-income individuals would pay into Medicare, up from 1.45%. High-income is defined as individuals making more than $200,000 ($250,000 for couples filing jointly).

2014 -- The year that people who don't buy insurance will be penalized $95 or up to 1% in income.

19.1% - Percentage of people living in the South who are uninsured, the highest percentage of any region in the U.S.

24.6% - The percentage of uninsured people in Texas, the highest of any state.

5.6% - The percentage of uninsured people in Massachusetts, the lowest of any state.

Basics: Health care reform issues