Durham – Nearly one in four potential voters statewide didn't live in New Hampshire in 2000, according to a University of New Hampshire report released yesterday, a fact that could have strong implications for next month's first-in-the-nation presidential primary.

While New Hampshire's population has remained relatively steady, growing by 21,000 from 2001 to 2005, the actual migration patterns have been anything but, according to a demographic report from UNH's Carsey Institute. During that time period, 210,000 people moved into the state while 189,000 moved out, with a full 78,000 coming from Massachusetts.

►View the report (PDF file)

"I'm sort of stunned at the volume that produced this modest change," the report's author, Senior Demographer Kenneth Johnson told the New Hampshire Union Leader. "Four hundred thousand people turning over in a state of 1.3 million, that's a lot of change."

Two trends helped fuel the radical population shift: Massachusetts residents and retirees. Many of those coming into the state are families moving into the southern tier and older people taking up residence in the Lakes Region and recreation-focused areas in the north.

The huge numbers of new residents statewide may play a pivotal role in the primary on Jan. 8, with many ex-Massachusetts residents leaning redder than previously thought, according to Dante Scala, an associate professor of political science at UNH.

Scala said the tens of thousands of former Massachusetts residents likely left that state because of its higher taxes and more expensive housing prices and because of that may lean toward Republican candidates.

"They're more in keeping with the old kind of New Hampshire political culture, which is 'leave us alone,'" he said. "They're the ones who found New Hampshire more congenial. They bring their politics with them."

A May 2006 UNH Survey Center poll of ex-Massachusetts residents lends weight to that argument. Of those surveyed who moved from the Bay State to the Granite State, a full 35 percent said the thing they'd miss least about Massachusetts was the high taxes, while 38 percent said that the "political leadership in Massachusetts" was at least a "minor factor" in their reason for moving.

"It's possible they may go with (former Massachusetts Gov.) Mitt Romney because when he talks about having to govern Massachusetts, they know exactly what he's talking about," Scala said.

All those families also brought money with them as well as children, the report says, with departing residents taking about $5.31 billion in income with them and arriving residents carrying $6.73 billion in income.

"Twenty-somethings go to Boston because it's where the action is and it's a cool place to go, but when they start to have kids, they think, 'Where do I raise this family,' and then New Hampshire becomes more attractive," Johnson said.

The report also shows New Hampshire is attracting a significant number of older residents, a trend that is only expected to increase with the baby boom generation preparing to retire.

"The number of old adults in the state will increase rapidly in the next two decades because of two distinct demographic processes: current residents will continue to age in place and older migrants will continue to settle in New Hampshire," the report says, noting that the state has 156,000 people aged 55 to 64 and 217,000 aged 45 to 54.

Scala said those retirees are helping to reshape the political landscape in northern portions of the state, including Grafton and Carroll counties, where many of them move to find a nice place to live out their twilight years.

"Those are areas that were once very very Republican and they've become increasingly Democratic," Scala said. "Something has to explain why those counties are not voting as Republican as they once did."

The numbers show that New Hampshire is quickly becoming a state made up of migrant residents. Nearly 57 percent of current residents were born elsewhere, compared to a national average of just 40 percent, the report says.

The report also sheds light on the reasons behind a previously recognized, and widely discussed, trend: the state's shrinking young person population.

The report shows that the young person decline in New Hampshire is a result of far fewer babies being born during the 1970s than the 1960s rather than young adults leaving the state.

"It's not that they're all bailing on the state, in fact it looks like there are more coming in than leaving right now, in fact it's a demographic phenomenon," Johnson said. "I think that's important because it has significant policy implications."

Like many other states, New Hampshire experienced an explosion in the minority population from 2000 to 2006, though the state remains one of the whitest in the country with 93.7 percent of residents being non-Hispanic white.

New Hampshire's Asian, Hispanic and African American populations all grew more than 40 percent since 2000 with the total minority population rising 24,000 to 82,000 people.