The Massachusetts economy added 6,600 jobs in December as the state's unemployment rate continued its downward trend, hitting its lowest level in 16 years.

The state's total unemployment rate ticked down one tenth of a percentage point to 2.8 percent last month -- the sixth straight month it has declined, the Executive Office of Labor and Workforce Development reported. The last time the jobless rate was as low as 2.8 percent was December 2000.

"For the past six months, the unemployment has continued to drop, and the labor force participation rate has held steady over the year, which is very good news for the state," Labor and Workforce Development Secretary Ronald Walker said in a statement. "We are also pleased to see the state continues to add jobs in key sectors, such as Education and Health Services, Professional, Scientific and Business Services, Information, and Construction."

The Massachusetts jobless rate has remained lower than the national unemployment rate since April 2008. The national rate for December was 4.7 percent, according to the U.S. Bureau of Labor Statistics.

State officials also reported Thursday that Massachusetts added 7,000 jobs in November, more than the 5,800 jobs originally reported for that month.

The nation is in the midst of its eighth straight year of economic expansion. In the two years since Gov. Charlie Baker took office, Massachusetts has added 116,000 jobs and its unemployment rate has dropped from 5.5 percent to 2.8 percent, according to data provided by the state.

Since the statewide unemployment rate hit its most recent apex of 8.8 percent in September 2009, 335,600 more Massachusetts residents are employed and 202,700 fewer residents are unemployed, the labor office said.

The latest jobs numbers come one day before President-elect Donald Trump is to take the oath of office. On the campaign trail last year and during the transition, Trump has pledged to create a total of 25 million new jobs for the American economy over the next decade.

A Trump administration federal stimulus plan, Northeastern University economist Alan Clayton-Matthews said this week, will likely boost job growth in Massachusetts in the short term. But "future growth potential is constrained" due to a slower increase in the number of available workers as the Baby Boomer generation retires and because the economy is at or near full capacity, Clayton-Matthews wrote in a forecast of the Massachusetts economy through 2020.

"In 2016, the labor force is projected to have grown by 0.7% over 2015, but by 2020, labor force growth is expected to slow to 0.3%," he wrote in the New England Economic Partnership forecast. "This is the primary reason why rates of job growth are declining in the last several years of the forecast period."

Also of significant concern, Clayton-Matthews said, is the uncertain future of the Affordable Care Act, which has driven spending into the health care sector. Federal aid for Medicaid expansion and subsidies for the Massachusetts Health Connector were expected to total $29 billion over the next five years.

"If this support diminishes or disappears, to what extent would or could the state step in to maintain existing benefits?" Clayton-Matthews wondered in his forecast. He also said federal support for medical science research "may also be in jeopardy, which would have an impact in Massachusetts, and said policies that limit or discourage immigration would have an impact on the state's available pool of workers and affect higher education institutions that serve foreign students.