Between January and June, about 45.4 million people in the U.S. had no health insurance, according to new government data.

Between June 2008 and last June, 58.4 million people were uninsured for at least part of the year, and 31.9 million people had been without insurance for more than a year, according to U.S. Centers for Disease Control and Prevention’s National Center for Health Statistics. The results are based on interviews.

The estimates were released within hours of the U.S. Senate’s approval of a measure it says would provide coverage to another 31 million people, according to the Congressional Budget Office. Meanwhile, a competing U.S. House bill has different provisions, leaving legislators the task of having to resolve the conflicts before passage of a final health care reform bill.

Several interesting trends emerged from the data. People between 18 years old and 24 years old had the highest uninsured numbers, with 29.6% not being insured. The least likely to lack coverage for people under 18 years old; just 8.2% did not have coverage, owing in part to the spread of State Children’s Health Insurance Program (SCHIP).

Researchers said public coverage rates among both children and adults aged 18-64 years are higher now than in 1997; conversely, private health care coverage rates among both children and adults aged 18-64 are lower now than what was reported in 1997.

Men were more likely than women under the age of 45 to be uncovered, while between 45 years old and 64 years old, no difference in coverage levels between sexes was evident, researchers said.

About 20% of people under age 65 were covered by public health plans and nearly 64% were covered by private health plans between January and June of this year. Two-thirds (66.8%) of adults aged 18-64 were covered by a private plan, compared with 56.3% of children under age 18.

More than one-third of children (37.4%) were covered by a public plan, compared with 13.7% of adults aged 18-64. The percentage of children covered by a public health plan increased from 34.2% in 2008 to 37.4% in the first six months of this year.

Hispanic people had the highest probability of being uninsured, with nearly one-third lacking coverage for part of the year, and more than 25% being uninsured for more than a year.

Researchers found that from January to June 2009, the percentage of children under age 18 years who were uninsured at the time of interview was 8.2%.

About 61% of unemployed adults between the ages of 18 and 64 were without coverage for at least part of the year, while 21.8% of employed adults were uninsured for at least part of the year. Nearly 33% of unemployed adults in this age group and 13% of employed adults were uninsured for more than a year.

From January to June 2009, 60.6% of unemployed adults aged 18-64 years and 21.8% of employed adults in this age group had been uninsured for at least part of the past year. Also, 32.9% of unemployed adults aged 18-64 and 13.3% of employed adults in this age group had been uninsured for more than a year.

The estimates on health insurance coverage for the civilian non-institutionalized U.S. population is based on data from the January 2009-June 2009 National Health Interview Survey (NHIS), which relies on interviews with 32,694 people, along with comparable estimates from the 1997-2008 NHIS.