PORTLAND – Maine had the nation’s lowest birthrate in 1998, according to figures from the state’s Office of Data, Research and Vital Statistics.

Maine also had the lowest birth- rate and the highest age-adjusted death rate in New England that year, the most recent year for which figures are available.

In 1998, Maine women gave birth to 13,720 babies, a figure that represents a half-percent increase from the previous year. It was the first increase the state saw since 1990.

In 1998, 12,070 Maine residents died. In seven counties – Aroostook, Hancock, Knox, Lincoln, Piscataquis, Oxford and Washington – more people died than were born.

In 1997, Maine had the fourth oldest population, behind Pennsylvania, Florida and New York. That means Maine has a lower percentage of women of childbearing age than the rest of the nation.

Maine’s ethnic and racial homogeneity also contributed to the low birthrate. Hispanics and blacks tend to have higher birthrates than whites. According to census figures released last month, 97 percent of Maine residents identified themselves as white. Those identifying themselves as Hispanic, which is considered an ethnic and not a racial category, made up less than three-quarters of one percent.

“In the country as a whole, the birthrate for white women is also falling,” said Charles Colgan, professor of public policy and management at the Muskie School of Public Service. “It’s just that [in Maine] we have no populations with larger birthrates that are offsetting the decline among the white population.”

In-migration was a mere trickle between 1997 and 1998, when Maine had a net gain of just 696 people.

“That’s the smallest number of in-migrants in 18 years,” said Deirdre Mageean, interim director of the Margaret Chase Smith Center for Public Policy and associate professor of resource economics and policy at the University of Maine.

Some European countries, including Italy, are struggling with declining birthrates and are concerned about how a shrinking work force will sustain their economies, Mageean said.

“To alter our older profile, you would need years of sustained in-migration,” she said. “It took us a long while to get to this point, and it would take us a long while to reverse the trend.”

If the birthrate continues to decline and people move out of the state without others moving in to replace them, “we won’t have to worry about sprawl because there won’t be much of an economy left,” Colgan said. “There will be literally no job growth because there’s no labor force.”