Technology glitches have frustrated many consumers trying to sign up for coverage online, and efforts to upgrade and repair healthcare.gov are ongoing.
But the estimates, obtained through a public records request, may be the closest thing to a yardstick for measuring the performance of President Barack Obama's health care law across the states.
The enrollment breakdown by states was included in a draft of an administration report on insurance premiums in the new markets, but it was omitted from a subsequent version that was released to the public last month by the Department of Health and Human Services.
Leading up to the opening of insurance markets Oct. 1, the White House generally deflected questions about its own expectations of how consumers would respond. Officials instead cited a congressional estimate that 7 million people would gain coverage in the first year through the markets, which offer subsidized private insurance to people who don't have a job-based health plan.
The draft, dated Sept. 20, broke down the figure of 7 million among states. It estimated the expected enrollment in California, for example, at 1. 3 million people in 2014. The estimate for Texas was 629,000 and for Florida, 477,000. The report estimated 340,000 people would enroll in Washington state, and 218,000 in New York.
The final report, released Sept. 25, omitted the enrollment estimates, but it was identical in most other respects.
Asked why the estimates were missing from the final report, HHS spokeswoman Joanne Peters said in a statement: "We are focused on reaching as many people as possible about their options. There are many estimates of how many people will enroll in year one." Some states have released their own estimates, she added, and other states are changing theirs based on experience.
The omission puzzled some experts in the field.
"Why there is this reluctance to share internal estimates, I don't know," said health economist Gail Wilensky, who ran Medicare for President George H.W. Bush. "This kind of information has a way of worming its way out into the open, which makes it look like they have something to hide."
While consumer interest in the new health insurance markets has been undeniably strong, it's hard to get a sense of how many people have been able to navigate balky federal and state websites and successfully enroll. Numbers released by states running their own marketplaces suggest upward of 100,000 people have enrolled so far, out of millions of potential interested customers.
The administration refuses to release numbers for the 36 states in which it is taking the lead. Officials at first said the frozen computer screens and other issues were the result of a high volume of interest. They later acknowledged software and design issues were also to blame.
HHS belatedly rolled out a feature that allows consumers to get a look at health plans in their area without first establishing an account. The requirement that people set up an account before shopping was at odds with the normal way e-commerce websites are run, and was blamed for overloading the system.
Appearing earlier this week on MSNBC, former White House spokesman Robert Gibbs said the situation is "excruciatingly embarrassing" for the administration.
"This was bungled badly," said Gibbs, adding: "When they get it fixed, I hope they fire some people that were in charge of making sure this thing was supposed to work."
Although Gibbs did not refer to HHS Secretary Kathleen Sebelius, White House spokesman Jay Carney said Tuesday she has "the full confidence of the president."
The potential political fallout from the troubled launch of the insurance markets isn't the major issue, however. There are bigger concerns for the impact on average Americans and, if signups remain anemic, on federal taxpayers.
The more uninsured people who buy coverage, the sooner they'll have access to services -- well-patient checkups and prescription drugs among them -- to help them improve their health and avoid a crisis that could be far costlier than preventive medicine. Their children will have access to services, too.
Just as important, robust enrollment by younger, healthier people is critical because older people and people with illnesses, who are more expensive to insure, are highly motivated to sign up. Insurers will be relying on revenue from policies they sell to younger people who need fewer services to help make up the difference.
An insurance pool tilted toward older, sicker people also would raise costs for the government, which will be subsidizing the coverage.
The AP obtained a copy of the federal enrollment estimates in a public records request with Idaho's health insurance marketplace, Your Health Idaho.
Uninsured people have until Dec. 15 to sign up for coverage to take effect Jan. 1, when most Americans will be required to have health insurance.
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