(old Highline, courtesy of abc.com)

New York City lost less population to other states in the 12 months ending July 1, 2008, than during any year in decades, according to census figures released Thursday. If that trend continues, the city’s population will top 8.4 million in 2010.

Gains and stanched losses in New York and a number of other large metropolitan areas in the Northeast, the Midwest and coastal California reflected, in part, slower growth in traditional domestic migrant magnets in the South and West.

An analysis by William H. Frey, a Brookings Institution demographer, found that Las Vegas, Orlando and Tampa drew fewer migrants than in any year in nearly two decades. Phoenix attracted only half as many as two years earlier. Booming Riverside-San Bernardino, near Los Angeles, recorded the first migration loss since the mid-1990s.

“The beneficiaries of this bursting migration bubble include large metro areas whose earlier high housing prices made the exurbs and interior metro hot spots seem too tempting to pass up,” Dr. Frey said.

Other demographers agreed that the reversals were stunning.

“This is one of the most complex patterns of migration change in a short period that I have seen in 30 years,” said Kenneth M. Johnson, a sociology professor at the University of New Hampshire.

“This is new, a real deviation from the average,” said New York City’s chief demographer, Joseph J. Salvo. “Whether it’s a trend is another thing.”

The latest census estimate did not reflect the decline in private-sector jobs in the city late last year.

Dr. Salvo, the director of the Department of City Planning’s population division, said, “When you take a look at the conditions in the rest of the country and what has happened to the housing and economic market in a lot of places our migrants have gone to, it’s very tempting to conclude that perhaps people are staying put more because the opportunities that were afforded there are not there any longer or are no longer attractive.”

As of July 1, 2008, the census counted 8,363,710 New Yorkers, an increase of 355,000, or 4.4 percent, since April 2000. As a result, New York City residents now account for nearly 43 percent of the state’s population.

In the year beginning July 1, 2007, the city grew by nearly 54,000, with Brooklyn registering the biggest increase. During that year, 76,000 more people left the city for other states than arrived from other states, a sharp reduction from the annual average since 2000 of 148,000.

While immigration from abroad has slackened some since the 1990s, the net influx of 73,000 foreigners was nearly enough to offset the domestic outflow. Also, longer life spans and higher birthrates among immigrants contributed to there being 63,000 more births than deaths.

“A growing population is one of the best defenses against housing abandonment and economic decline,” Mayor Michael R. Bloomberg said.

In the metropolitan area, Nassau County, on Long Island, and Essex County, N.J., recorded losses in the latest year. Hudson County, N.J., and Fairfield County, Conn., reversed earlier losses registered in the middle of the decade.

Los Angeles and Cook County, Ill., which includes Chicago, reversed recent losses, too.

While some places expanded more slowly than in prior years, most of the fastest-growing areas between July 1, 2007, and July 1, 2008, were still in the South and West. Raleigh-Cary, N.C., grew faster than any metropolitan area. St. Bernard Parish, La., was the fastest-growing county.

Metropolitan Dallas-Fort Worth, Houston, Phoenix and Atlanta each added more than 100,000 people in a year when 313 areas gained population and 50 lost. Most of the fastest-growing counties and metro areas were in Texas, Georgia, North Carolina, Utah and Idaho.

An analysis by Mark Mather and Kelvin Pollard of the Population Reference Bureau found that the population in counties with unemployment rates of 6 percent or more in 2007 grew by 0.3 percent, compared with 1.2 percent growth in areas with unemployment less than 4 percent.

While all but two states (Michigan and Rhode Island) gained population, they found, more than a third of the nation’s counties recorded losses.

Demographers agree that unemployment may be just beginning to affect migration patterns.

Dr. Johnson, who is the senior demographer at the Carsey Institute at the University of New Hampshire, said: “Migrants to metro cores tend to be younger adults, 20 to 29, who are less concerned about the housing market and more concerned about the job market. So, my best guess is that through the period covered by the census data they would have still come.

“On the other hand, those leaving metro cores tend to be in their 30s and 40s with children, so the housing market, particularly selling houses, is a big deal to them. The slowdown of the housing market has essentially frozen them in place. As a result, big metro cores are losing fewer people and continuing to gain young ones.”

Dr. Frey said the next round of census figures would better capture any trend. “Because these numbers do not yet include the substantial rise in unemployment that has occurred in the past several months,” he said, “there is no telling how much more air will be let out of the mid-decade migration bubble before the housing and labor markets begin to revive.”