The Gallup-Healthways Well-Being Index was based on 9,000 interviews with U.S. adults conducted Jan. 2 to 19.
This is a preliminary snapshot of the uninsured rate in this month, after several provisions of the Affordable Care Act, commonly known as "Obamacare," took effect.
However, long-term impact of the Affordable Care Act on the uninsured will take months to determine. The uninsured have until March 31 to buy health insurance or be fined.
The uninsured rate so far in January has declined more among those unemployed than it has among those employed. The unemployed remain the subgroup with the highest uninsured rate at 34.1 percent but the initial decline among this group suggests the healthcare law might be working as intended for unemployed adults, Gallup said.
Additionally, the uninsured rate has fallen more among non-whites than whites. The uninsured rate among non-whites so far in January is 26.5 percent, compared with 29.1 percent last December.
These preliminary results indicate that, so far, uninsured rates have not declined disproportionately among younger Americans, who continue to be more likely to be uninsured than older Americans.
The survey of 9,145 U.S. adults was conducted Jan. 2-19. It has a margin of error of 1 percentage points.