According to a recent Census Bureau report, in 2010:

• The overall rate of employment-based health insurance coverage was 56.5%, down from 64.4% in 1997
• 43.3% of Individuals with family income less than 138% of the federal poverty level were employed in firms that offered health insurance benefits (100% of the federal poverty level for a family of four was $22,113 in 2010)
• 80.9% of workers with family income 401% and above of the federal poverty level worked for an employer that offered health benefits
• Among workers whose employer offered health insurance benefits, but who did not participate, 50.4% declined coverage by choice
• The two most common reasons among workers who chose not to obtain health insurance coverage through their employer: health insurance obtained through another source (66.4%) and cost (27.4 %)
• About 1.1% of nonparticipating workers were not insured by their employer's health insurance because they were denied coverage

Source: "Census Bureau Reports Decline in Employment-Based Health Insurance, " U.S. Census Bureau Press Release, February 27, 2013, http://www.census.gov/newsroom/releases/archives/health_care_insurance/cb13-35.html