>>Collier County has a lot to thank Cook County, Ill., for. And Hennepin County, Minn., and Geauga County, Ohio, right outside Cleveland.

Each year, people move to Southwest Florida from throughout the country, bringing their salaries, pensions and other assets and income with them, fattening local coffers, supporting jobs and sustaining the region's economy.

The strength of any economy is based on how long it can keep dollars circulating within the region, and although Collier County still has a strong agricultural base, Southwest Florida as a whole doesn't manufacture or produce much in the way of goods to sell to other regions. Instead, it draws its dollars from tourism and newcomers, and keeps them here by serving those people.

According to statistics from the Internal Revenue Service, Cook, Hennepin and Geauga counties are among the leading points of origin for Southwest Florida newcomers. In 2003-2004, Cook County emigrants brought $35.2 million in aggregate income, Hennepin County emigrants contributed nearly $20.4 million, and Geauga County accounted for $17.4 million.

That story hasn't changed much over the past decade. Cook and Hennepin counties also hit the top three in 1994-'95 and in 1999-2000. St. Louis County, Mo., and Milwaukee County, Wis., slipped into the third and second slots, respectively.

"It's definitely a leakage to [those counties'] economy. For us, it's a plus," says Moji Abimbola, an economist with the Southwest Florida Regional Planning Council.

The influx is "very important" to Southwest Florida's economy, she says. "The bulk is coming from seniors. They make it work." Their needs and demands create jobs. "Younger people don't bring [dollars] with them," she adds, but they help keep it here by getting jobs here, earning money, "and hopefully spending what they earn here."

"From a government perspective, it's made state coffers flush," says University of Florida economist David Denslow. "[Florida benefits] from a combination of sales tax on house construction, furniture, doc-stamp taxes, increase in property tax revenue, spilling over into restaurant and gas stations and everything else."

Immigration creates the need for greater infrastructure, social services and other public expenditures, but Florida's economy has long been tied to the arrival of newcomers, and the state's growth is closely related to the retirement population.

"It's been going on a long time, but it was slow during the 1990s," says Denslow. "Now we're seeing a resurgence of how they were during '70s and '80s."

As baby boomers build and buy houses in anticipation of retirement, and with more "footloose workers-because of the Internet, they can work anywhere," he explains, "it is a phenomenon of a different magnitude."

Although the influx is good news for Southwest Florida's economy, the loss strains some of those donor areas where new population and dollars are failing to replace those that are lost.

Cuyahoga County, Ohio, which includes Cleveland, has seen a steady drain to neighboring counties as well as to places like Southwest Florida, says Robert Layton, principal economic planner for the Northeast Ohio Areawide Coordinating Agency, which deals with transportation planning for a five-county region around and including Cuyahoga.

The region's population of 2.1 million is the same as in 1960, says Layton, and it has shifted from urban Cleveland to the suburbs and exurbs, taking employment with it. "Twenty years ago, people who moved out [of the city] still drove into Cleveland for a job."

The sprawl and emigration to places like Florida are straining Cleveland's ability to provide urban services and the region's infrastructure, says Layton.

IRS statistics show that 244 federal income tax returns in 2003-2004 were filed in Charlotte, Collier and Lee counties by people who had moved from Cuyahoga, bringing with them aggregate income of $29.7 million. A 2003 report by The (Cleveland) Plain Dealer cites a loss of $238 million to Collier and Lee counties from 1996 to 2003.

"The basic economy of Northeast Ohio, historically bounded in steel and heavy industry, is never going to return. The entire industrial crescent is gone," says Layton. The region's economy now is reliant largely on healthcare and other service sectors.

"Certainly, if the spending that's lost [to other areas] were here, it would create more jobs," he says. "The spending that leaves probably would help support some of the services," as well as the entertainment industry, including the arts and professional sports.

"The amount of money that actually leaves [as of a few years ago] is 1 to 2 percent of the total earned here, but it's increasing every year, gradually," says Layton. "It's not as though half the income is leaving, but the trend is increasing, which will probably continue for the foreseeable future with the baby boomers starting to retire.

"I'm not sure how much it has to get up to before we start to hurt," he adds.

More immigrants and dollars flow into Southwest Florida from Cook County, Ill., in the Chicago area, than Cuyahoga, but it hasn't felt any significant impacts, says the county's economic development director, Jackie Harder.

"It's true some people have a second home, but a lot of people maintain their primary residence [in Cook County]," she says, and newcomers fill the gaps that are left by emigrants. Plus, she anticipates that many who retire to the sunny South will return.

"My parents' generation has gone South, but I also hear them talk about the fact that eventually they move back North to be with their families in their real declining years," she says.

Layton points out that a recent U.S. Census report shows Florida, along with other Sunbelt states, as one of the leading destinations for domestic migration. It's a pattern that concerns him as more frequent and more violent hurricanes hit Florida and the Gulf states, and as the pressue on water supplies in Arizona and New Mexico grow worse with growing populations.

"On top of that, if you believe in global warming, there are some long-term issues that are going to start being pretty severe. I just wonder how many Katrinas can we, as a nation, afford," says Layton. "I don't know if the long-term trends of movement are sustainable," he adds. "As a nation, the movement of our population is a movement in the wrong direction."

Harder also wonders how long Southwest Florida's charms will last.

"Retirement flow has been for many years to the south, but I don't know if that's going to continue.

"Some areas down there are getting very congested," she says. "My parents live in Sarasota. They say it's awful in the winter. They can't even go out to restaurants."