NEW YORK (CNNMoney) -- For the first time in four years, the number of Americans without health insurance decreased.
The U.S. Census Bureau reported Wednesday that 48.6 million people were uninsured in 2011 -- down from 50 million the year before.
The percentage of uninsured people also ticked lower, edging down to 15.7% from 16.3%.
For the fifth consecutive year, the percentage of people covered by government health insurance increased -- up to 32.2% from 31.2% in 2010.
People covered by Medicaid increased to 16.5% from 15.8%, and Medicare coverage edged higher to 15.2% from 14.6%.
At the same time, young adults saw a boost in coverage from the provision of the Affordable Care Act that allows parents to keep their children on their policies. That piece of health care reform kicked in in September 2010.
The percentage of young adults ages 19 to 25 who were uninsured decreased in 2011 to 27.7% from 29.8%.
For adults between 26 and 64 years old -- for whom the major parts of ACA coverage expansion won't go into effect until 2014 -- the uninsured rate was not statistically different, the Census Bureau found.