From the AMA:

Employer-sponsored coverage has declined steadily since Gallup began tracking health insurance in 2008. At the end of that year, about 50% of those polled received insurance through an employer. A Gallup Poll from the third quarter of 2011 provides a breakdown of health insurance coverage. Among U.S. adults:

44.5%: Insured through an employer 
25.1%: Insured through a government plan 
17.3%: Uninsured 
11.4%: Have some other type of coverage 
1.7%: Don't know/refused to answer/not applicable

The Commonwealth Fund found that from 2003 to 2010:

• Average total premiums rose by 50%.
• Average annual employee share increased by 63%.
• Average per-person deductible increased by 98%.
• If the rate of growth in insurance premiums from 2003 to 2010 holds, the average annual premium for family health coverage will near $24,000 by 2020, or about $2,000 per month.

Source: "State Trends in Premiums and Deductibles, 2003-2010: The Need for Action to Address Rising Costs," Commonwealth Fund, Nov. 17