Those newfangled Obamacare plans can be pretty cheap—especially if the government is helping you pay for them.
In fact, 69 percent of enrollees who bought HealthCare.gov-sold insurance plans with government subsides ended up paying $100 or less per month in premiums, officials revealed.
And 46 percent of those subsidy-eligible enrollees in the health-care exchange paid $50 or less per month in premiums, said federal officials.
Those averages are significant because the overwhelming majority—87 percent—of the 5.4 million people who bought health insurance through HealthCare.gov by mid-April did so using subsidies. Those tax credits are available to individuals who earn between about $11,490 to $46,000 per year.
"Tax credits matter," said a senior official in the U.S. Health and Human Services Department, who spoke on the condition he not be identified by name as he briefed reporters on data from the first year of the health-care exchange sales.
The average enrollee with a subsidy who opted for a "silver plan" on HealthCare.gov paid just $69 per month, according to officials. That is 80 percent less than the average monthly premium—$345—for silver plans sold on that exchange, which enrolled residents of 36 states.
Silver plans were the most popular grouping of insurance plans sold on the health-care exchange, with 69 percent of enrollees on HealthCare.gov opting for them. On average, such plans personally cost enrollees about 30 percent of the covered health benefits.
The average subsidy-eligible enrollee in any type of plan—bronze, silver, gold or platinum—paid an average of $82 per month, officials said. That is 76 percent less than the average price of those plans before tax credits, or $346 per month.
"That is a significant discount, on average," noted a senior HHS official.
The groups, named for metals, reflect the cost structure of their plans. As a rule, bronze plans cost less in premiums than other plans, but their enrollees are responsible for a higher share of out-of-pocket costs. Platinum plans have the highest monthly premiums, but enrollees foot less out-of-pocket costs.
Officials said they did not have data about the average post-subsidy prices paid by enrollees on the 15 exchanges run by individual states and the District of Columbia, although they noted that the prices of some silver plans in those states were not markedly higher than those on HealthCare.gov.
Those other exchanges sold plans to 2.57 million people by the end of open enrollment for Affordable Care Act individual policies in mid-April. Each of those exchanges have their own websites, but HealthCare.gov also acts as a portal directing residents of those states to the appropriate exchange.
Nor did officials have updated data on how much they expect it will cost the federal government to subsidize the cost of insurance for individuals who were eligible for those tax credits when they enrolled in Obamacare plans.
The Congressional Budget Office two months ago estimated that the government would spend $17 billion in 2014 for "exchange subsidies and related spending."
Officials also said Wednesday that nationally—on all health-care exchanges—the average shopper could choose from five health insurers offering 47 different insurance plans.
They also noted that 82 percent of shoppers had between three and 11 insurers to choose plans from, and 96 percent lived in areas with at least two insurers selling plans through the health care martketplace. In all, there were 266 issuers of insurance on the exchanges, offering more than 19,000 plans.
"What we're finding is that the marketplace is working," said U.S. Health and Human Services Secretary Sylvia Burwell, in a prepared statement issued by HHS. "Consumers have more choices, and they're paying less for their premiums."
Burwell was not on the conference call with reporters that senior HHS officials held Tuesday afternoon to discuss the data, which was embargoed until Wednesday. That call was conducted on background, meaning that reporters could quote the participants' comments, but could not identify them by name.
Several reporters questioned the rationale for those ground rules. An HHS spokeswoman said the agency was relying on a press release that included Burwell's brief statement to be its official on-the-record comment, and was holding the call to provide context for the media.
Officials said they did not have data on what percentage of enrollees paid their first month's premiums, which is required for their enrollment to be official, and coverage to be in effect. They said they would have that information later this year.
HHS also said it does not yet have information that can be made public about how many enrollees each insurer signed up for their plans on the exchanges.
Officials said some of that data "is proprietary information."
—By CNBC's Dan Mangan