The uninsured rate for American adults keeps dropping and according to a Gallup poll relased today, has hit the lowest level since Gallup and Healthways started tracking in it Jan. 2008.

In the third quarter of 2013, the uninsured rate peaked at 18.0 percent, but has been on a steady decline since, dropping to 15.0 percent in March and 13.4 percent in April.

The sharp decrease in the uninsured rate coincided with the opening of the health insurance marketplace exchanges.

Overall, the uninsured rate has fallen the most for minorities and lower-income Americans.

The rate dropped more among blacks than any other demographic group, falling 7.1 percentage points to 13.8%. Hispanics were expected to disproportionately benefit from the Affordable Care Act — commonly referred to as “Obamacare” — because they are the subgroup with the highest uninsured rate. Although the percentage of uninsured Hispanics, at 33.2%, is down 5.5 points since the end of 2013, this rate is still the highest by far across key demographic groups.

Similarly, the uninsured rate among lower-income Americans — those with an annual household income of less than $36,000 — has also dropped by 5.5 points, to 25.2%, since the fourth quarter of 2013.

The uninsured rate among young Americans (18- to 25-year-olds) is at 19.0 percent, a decrease of 4.5 percent from the fourth quarter of 2013.