This post has been updated with newly released data from Gallup Wednesday afternoon.

New surveys out Wednesday morning provide a glimpse into just how many Americans have gained insurance since the Obamacare health insurance marketplaces opened in October.

First, Gallup reports that states which fully embraced the law by setting up their own exchanges and expanding their Medicaid programs saw their uninsured rate drop this year three times faster than the states that didn’t.

Gallup just last week reported that the uninsured rate had dropped from 17.1 percent to 15.6 percent between the fourth quarter of 2013 and the first quarter of 2014 — the lowest rate since 2008. It's not all that surprising that states which have embraced the law have seen a larger decline in the uninsured rate. They have more resources for outreach and greater enthusiasm for getting people enrolled.

Meanwhile, the Urban Institute has further details on its finding that the number of uninsured nonelderly adults fell by 5.4 million people between September and early March. Urban finds that states that expanded their Medicaid programs saw their uninsured rate drop 4 percent, while states that didn't expand saw a much slower drop at 1.5 percent. The expansion states also did a better job of covering young adults and especially Hispanics — demographics targeted by supporters of the health-care law.

A few notes here about the Urban numbers: first, the survey doesn't cover the last few weeks of March enrollment, when there was a surge in those signing up on exchanges. Second, the Urban results have a margin of error of 2.2 million at a 95 percent confidence rate, so it says the drop in the uninsured could be anywhere between 3.2 million and 7.6 million. Finally, Urban says it's too early to say definitively how exactly the Affordable Care Act contributes to the drop in the uninsured:

We find larger coverage gains in the states that expanded Medicaid for adults, overall and specifically among adults with incomes at or below 138 percent of [the federal poverty level], but cannot definitively attribute those differences to the Medicaid expansion because expansion states differed from nonexpansion states in other ways that could affect changes in coverage over this period. In particular, states that expanded Medicaid were also more likely to implement a state-based Marketplace as opposed to relying on the federally facilitated Marketplaces, and the state-based Marketplaces had access to substantially greater resources for outreach and enrollment activities (Blumberg et al. 2014; Hill et al. 2014). Disentangling the effects of the range of state policy decisions being made under the ACA will require waiting for data from the federal surveys, which have larger sample sizes, longer time series, and more in-depth information.

There will be future surveys that give us a better understanding of how Obamacare is changing the uninsured rate. One of those will be the Census Bureau, which was the source of some controversy Tuesday after a report in the New York Times said an overhaul of the agency's survey methodology would make it difficult to determine the ACA's effect on the uninsured rate. The report raised some eyebrows on the right and left, but the Census Bureau said it will be able to measure the ACA's impact.

The Census Bureau Tuesday night said the new survey methodology, first announced in September 2013, will go into effect for data covering the 2013 calendar year. So, while it will be difficult to compare changes in the 2012 and 2013 uninsured rate, it should be possible to make a direct comparison between 2013 and 2014, the start of Obamacare's coverage expansion.

UPDATE: Another Gallup poll released late afternoon Wednesday found that 4 percent of Americans say they're newly insured this year, with slightly more than half (2.1 percent) reporting they received coverage through an ACA exchange. The rest said they received coverage from another source, which could either be Medicaid, an employer or a health plan purchased directly from an insurer. Another 7.5 percent said they had a new health plan that replaced an old one.

The poll also found that newly insured people are, on average, younger than the rest of the population. People between 18 and 29 years old accounted for 30 percent of the newly insured, though they represent just 21 percent of the population. However, the newly insured in this age bracket were much more likely to get coverage off the exchange (24 percent exchange vs. 37 percent off-exchange).

Gallup found the newly insured also tend to be lower-income and are more likely to get coverage through the exchanges, where people earning up to 400 percent of the federal poverty level can receive subsidies to help purchase insurance. HHS has previously said 83 percent of those purchasing through the exchanges received financial assistance.