Raising their hands, 46 new American citizens, from 31 countries, take the official oath of allegiance at a swearing-in ceremony at Portland's King Middle School in this Jan. 18 photo.

Maine continues to experience more deaths than births, but the population is increasing and diversifying, according to U.S. Census data released Thursday.

The U.S. Census Bureau released characteristics of the population for the nation, states and counties.

Maine’s population hit 1,338,404 million in 2018, up o.25 percent from 2017 and up 10,772 people, or almost 1 percent, since 2010. All numbers are as of July 1 in their respective years.

“The nation is aging. More than four out of every five counties were older in 2018 than in 2010,” said Luke Rogers, chief of the Population Estimates Branch at the Census Bureau.

In Aroostook County, for example, the median age rose 3.2 years from 2010 to 45.3 in 2018. That’s higher than the state’s average of 44.9 years old and the nation’s average of 38.2 years old.

Credit: Courtesy of U.S. Census Bureau

Penobscot County saw its median age rise 2.4 years over the same period to 42.4 years old in 2018, while Hancock and Cumberland counties were up 2.5 years, to 48.9 years old and 42.2 years old, respectively. Waldo was up 2.6 years to 46.6 years old in 2018, and York 2.2 years to 45.3 years old in 2018.

“This aging is driven in large part by baby boomers crossing over the 65-year-old mark. Now, half of the U.S. population is over the median age of 38.2,” Rogers said.

Maine had the largest increase in median age this decade, going from 42.8 years in 2010 to 44.9 years in 2018, making it the state with the highest median age in the country, the Census Bureau said.

Utah had the lowest median age in 2018, at 31 years. North Dakota was the only state to see a decline in its median age, from 37 years in 2010 to 35.2 in 2018.

Of the nation’s 3,142 counties, close to 82 percent had a higher median age in 2018 than in 2010.

As the nation continues to grow older, it also is changing by race and ethnicity.

Maine is following the nation in becoming more diverse. By race, Maine’s population of nonwhite residents is rising faster than that of its white residents, Rogers said.

“The white population rose by 2,415 people from 2017 to 2018, which is about 0.2 percent,” he said. “Black or African-American rose 2.9 percent in that year period and 35.4 percent since 2010. And the Asian population rose 2.2 percent last year compared to 24.8 percent since 2010.”

That’s similar to the changes the nation as a whole experienced since 2010, he said.

Maine’s Hispanic population also is on the rise, from 17,008 in 2010 to 22,850 in 2018.

Cumberland County continues to have the most black or African-American people, with 11,298 in 2018 of the total of 29,923. That’s up 29.4 percent since 2010. Androscoggin follows with 6,005 people, York with 3,178 and Penobscot with 2,277.

Penobscot County has the most Native American or Alaska Natives with 3,311 of the total of 20,629. That’s up 7 percent since 2010.

Looking at age across all race and ethnic groups, residents 65 and older in the state increased by 3.3 percent since last year to 275,999.

“That population grew rapidly from 2010 to 2018,” Rogers said. “It was up 30.8 percent.”

However, that population has eclipsed those under 18, who numbered 250,404 in 2018. That’s down almost 1 percent in the past year and down 8.8 percent since 2010.

In the under-18 group, the largest decline was in those between 5 and 9 years old. Their numbers were down a little more than 1 percent in the past year and down more than 8 percent since 2010.

The median age in Maine was 44.9 years old in 2018, higher than the 42.8 in 2010. That means the population aged 2.1 years since 2010. By comparison, the U.S. population aged an average of one year during that period to 38.2 years old.

The median age for white people was 46.1 in 2018, up 2.5 years from 2010.

And while other races also are experiencing higher median ages, they are younger than the median age for white people. Black or African-American people had a median age of 21.9 in 2010, but that rose 3.4 years from then until 2018. Native Americans or Alaska Natives were up 3.3 years to 36.3 years from 2010 to 2018. People of Asian descent were up 4.3 years to 35.5 as a median age. The median age of Hispanic people rose the most during that period, by 4.5 years to 28.4 years old.

Those numbers are higher than the national average. Throughout the United States, the median age of black or African-American people rose by 1.4 years, less than half the amount in Maine. Native American or Alaska Natives rose 2.2 years, less than the 3.3 years in Maine. The age for Asian people increased by 1.7 years, also far less than half the amount in Maine. And the age for Hispanic people rose 2.2 years, less than half the median age increase in Maine.