From the overview:
Employer-sponsored insurance coverage forms the backbone of the U.S. health insurance system, yet there are crucial weaknesses that have contributed to a growing number of uninsured Americans. Ultimately, the lack of employer-based coverage generates public costs in the form of taxpayer bills to fund public insurance or uncompensated care programs for care that would otherwise be paid for through insurance. This report quantifies those costs, using data from the Medical Expenditure Panel Surveys to estimate public program spending and uncompensated care costs for uninsured workers and their dependents. In 2004, uninsured and publicly insured workers and their dependents accounted for $45 billion in public costs. This includes $33 billion associated with public program insurance costs and $12 billion in uncompensated care costs. Public costs associated with uninsured and publicly insured workers and their dependents were 45 percent greater in 2004 than in 1999. All costs are reported in 2004 dollars.