The number of Americans without health insurance is rising, and it's not just those living in poverty who are affected. According to the Centers for Disease Control and Prevention's new Vital Signs report, 59.1 million people had no health insurance for at least some part of the 12-month period that ended in March of this year. That's up 400,000 people from 2009.

Of that 59.1 million people, about 50 million aged 18 to 64 years had no health insurance, according to the CDC– the most ever recorded in that age group.

The data is from the National Health Interview Survey covering 2006 through 2009 and the first quarter of 2010. Over that time, the number of people without insurance in the 18- to 64-year-old age group has increased an average of 1.1 million Americans per year. Half of the overall increase are among people with family incomes twice to three times higher than the federal poverty level of about $22,000 for a family of four.

Dr. Thomas Frieden, director of the CDC, says the numbers mean access to care is seriously affected. "Private insurance coverage has been falling steadily for at least the last 10 years," Frieden said. "The public insurance safety net helped cover children, but private insurance fell by 9 percent." The uninsurance rate is three times higher in adults than children, according to the CDC.

The report also found adults without health insurance were three times more likely to skip or delay care because of cost. Last year, more than 40 percent of adults aged 18-to-64 years who had chronic diseases such as diabetes, asthma or high blood pressure and didn't have insurance admitted they went without care. Such delays can lead to poorer patient outcomes and higher costs. One reason, according to Frieden, is that people without insurance are much less likely to have a regular doctor.

There are stark differences in health insurance coverage in state-to-state comparisons. In Massachusetts, because the state has strong policies on health care coverage, only 6 percent of adults are uninsured. In Texas, 29 percent of adults have no health insurance, according to the CDC.

The CDC says the Affordable Care Act is expected to cover up to 94 percent of people under 65 years by 2019. That's an additional 32 million Americans.

Another measurement of the uninsured, from the U.S. Census Bureau shows 50.7 million people were without insurance for 2009. The Census Bureau figure, reported in September, reflects how many people were uninsured for the full calendar year.