"The law is helping millions of young adults to obtain health coverage," says study lead author Gary Claxton, a Kaiser vice president and co-executive director of the Kaiser Initiative on Health Reform and Private Insurance. "In the past, many of these young adults would have lost coverage when they left home or graduated college."

High-deductible health plans are especially gaining popularity among employers, the survey reveals, as covered workers enrolled in this type of plan have increased from 8 percent in 2009 to 17 percent in 2011. Of those participating in HDHP, 31 percent of covered workers have at least $1,000 deductibles for single coverage. Another 12 percent have deductibles of at least $2,000.

High deductibles are more common in smaller firms, where half of workers have at least a $1,000 deductible, and 28 percent have at least $2,000 deductible or more. HDHP premiums, however, are lower than other plan types when paired with a health savings account, though the annual deductibles must be at minimum $1,200 for an individual and $2,400 for a family this year.

Grandfathered plans are also a significant coverage option, the survey finds, with 56 percent of covered workers falling into these plans, which are exempted from certain health reform requirements. Some of the exemptions include covering preventive benefits with no cost sharing and providing an external appeals process. To qualify, no significant plan changes can be made that reduce benefits or increase employee cost.

Twenty-three percent of covered workers are enrolled in plans that adjusted cost-sharing requirements for preventive services because of the health reform law that states non-grandfathered plans must provide certain preventive benefits without cost sharing. Another 31 percent of covered workers participate in plans that modified their preventive services because of health reform.