WASHINGTON -- More than 2.2 million Pennsylvanians under the age of 65 will pay over 10 percent of their income on health care costs next year, according to a report released yesterday by Families USA.

That figure represents nearly one out of every five of the state's non-elderly residents, which U.S. Sen. Bob Casey, D-Pa., called "stunning."

The overwhelming majority of these Pennsylvanians -- 87.1 percent -- have health insurance coverage, the report says. But the expense of health care still eats up a greater share of family and personal budgets.

"The bottom line is health care that people used to take for granted is becoming increasingly unaffordable," said Ron Pollack, executive director of Families USA, a Washington, D.C.-based advocacy group.

The organization released the study to coincide with the early stages of the 2008 presidential campaign, which already has seen a significant debate over the rising costs of health care in the U.S.

A nationwide report will be released next month.

Mr. Pollack said the increase stems in part from employers who pass the expenses of fast-growing health insurance premiums onto employees. Pennsylvanians also are facing larger out-of-pocket expenses, such as co-payments for doctor visits and prescription drugs.

Almost 500,000 Pennsylvanians lost their employer-provided insurance from 2000 to 2006, according to a report published earlier this month by the Economic Policy Institute, a think tank.

The Families USA study looked at pre-tax earnings, analyzing statistics from the U.S. Census Bureau and the Department of Health and Human Services.

From 2000 to 2008, the number of residents of the Keystone State paying more than 10 percent of their income on health care costs will have increased by 371,000 -- a figure larger than the population of Pittsburgh.

Over 21 percent of the state's residents fall into this category. The national average is slightly higher, at 23 percent.

The number of non-elderly Pennsylvanians paying more than 25 percent of their income on health care will reach 601,000 next year, an increase of 4.7 percent from 2000.

"In a word, this report is stunning," said Mr. Casey. "When you put it in the reality of a family budget, it is earth-shattering."

He places much of the blame on the Bush administration, accusing the president of inaction over the last seven years. He also faulted the president for blocking an expansion of the State Children's Health Insurance Program, or SCHIP.

Large majorities in the House and the Senate have approved the program's expansion, but there aren't enough votes in the House to override a presidential veto.

President Bush and GOP supporters have said they want to see SCHIP focus on children closer to the poverty level.

The three leading Democratic presidential candidates -- Sens. Hillary Clinton and Barack Obama and former Sen. John Edwards -- have all proposed health care plans aimed at extending coverage to approximately 47 million uninsured Americans. Mrs. Clinton and Mr. Edwards would mandate coverage.

Leading Republicans, including former Massachusetts Gov. Mitt Romney and former New York City Mayor Rudy Giuliani, prefer market-based approaches, such as tax credits.

The Families USA study focuses on the large number of Pennsylvanians who face growing health care costs even though they have insurance.

From 2000 to 2006, employer-provided health insurance premiums for family coverage increased from $6,721 to $11,801, according to a separate report released in October by the Pennsylvania Health Care Cost Containment Council, an independent state agency.

Michael Weinstein, a spokesman for Highmark Blue Cross Blue Shield, said Families USA neglected to look at local efforts to contain growing expenses in Pennsylvania, such as Gov. Ed Rendell's Prescription for Pennsylvania agenda.

"This is a national issue that we're all concerned about," he said.

"That's why Highmark is working with the Rendell administration and the General Assembly."

The insurance company's chief medical officer is a member of the governor's Chronic Care Management, Reimbursement and Cost Reduction Commission, which also includes officials from UPMC Health Plan, Pennsylvania Managed Care, Keystone Mercy and AmeriHealth Mercy health plans.

When he announced the commission's creation in May, Mr. Rendell said 78 percent of health care costs can be traced to about 20 percent of patients with chronic diseases.

His administration also is pushing a Cover All Pennsylvanians plan that would collect an assessment of 3 percent of annual payroll from employers that did not offer health coverage to their workers. Businesses have been critical of the proposal.

Ann Torregrossa, policy director for the Governor's Office of Health Care Reform, said Mr. Rendell hopes lawmakers will move on a bill by the end of the year.

The Families USA report, she said, reinforces what her office has been seeing in recent years.

"We have a train wreck that's happening as we speak," she said.

"It's a totally unsustainable situation that dictates immediate action by both the state and federal government."