From January through March 2010, 46.7 million people of all ages had no health insurance at the time they were interviewed, according to the latest report from the National Health Insurance Interview Survey.
And at least 59.1 million people of all ages said they had been uninsured for at least part of the year prior to the interview.
"There has been a generally increasing trend in the percentage of adults aged 18-64 who lacked coverage at the time of the interview," as well as for part of the year, from 1997 through the first three months of 2010, the report said.
Also, an increasing number of insured U.S. residents under age 65 enrolled in a high-deductible health insurance plan or a consumer directed plan.
The survey, performed by the Centers for Disease Control and Prevention, found 59.9% of unemployed adults between the ages of 18 and 64, and 22.6% of employed adults, lacked health coverage for at least a part of the past year, and 35.4% and 13.8% respectively were uninsured for more than a year.
The report found an increasing percentage of poor and nearly poor as well as not poor people under age 65 who received public health plan coverage but the trend was greatest for those in the "near poor" category, which saw the percentage grow from 24.3% in 1997 to 58.7% for the first three months of 2010.
The percentage of people under age 65 who had no insurance at the time of the interview in the first three months of 2010 increased slightly for all economic groups, from 17.4% to 17.5% but for those between the ages of 18 and 64, the percentage of uninsured went from 18.9% to 21.5% in that 14-year period. For those under 18 years, however, the situation over the last decade has improved considerably, from 13.9% uninsured in 1997 to 7.4% in 2010.
The figures are for the civilian, non-institutionalized U.S. population, based on phone interviews with 23,825 people, but is extrapolated to the general population.