Long Island’s changing economy is reshaping the ranks of its major employers, reflecting the rise of giant retailers, the shrinking of some big banks, and the growing importance of health care.

A compilation of most of the Island’s big employers also shows a decline in the last decade in the importance of large manufacturing operations and the near disappearance of workplaces like those of Grumman Corp. in Bethpage and Calverton that were mini cities into which tens of thousands of employees would stream each day.

Economies are always changing, and Long Island has changed considerably from its post-World War II status as predominantly a bedroom community for New York City. Long Island had 1.33 million jobs in November, up from 1.27 million a decade earlier, according to the state Labor Department. Small businesses dominate the Island’s economic landscape: About 90 percent of the 96,000 companies here employ fewer than 20 people, according to census data.

And the composition of the jobs here has shifted because of economic forces such as the recession of 2007-09, the rise of the Internet, the drop in Wall Street jobs in New York City, and the expansion of global trade.

The Island’s largest employer is Northwell Health. The giant network, which recently changed its name from North Shore-LIJ Health System, has 31,153 full- and part-time workers, about the same as in 2006, when it employed 31,715 here. Northwell Health is the largest private employer in New York State.

Also still high on the list: the state government, with 20,304 Long Islanders working for state agencies and universities. That number has dropped, however, by about 4,700, as governments on all levels have sought to quell taxpayer dissatisfaction by reducing costs, including trimming jobs. The same holds true for the federal government — still a giant issuer of paychecks to Long Island, but down 1,670 since 2006, to 16,391.

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Determining the changes in Suffolk and Nassau counties’ employment totals since 2006 is difficult because it is unclear if the figures provided by the counties then and now are comparable.

Nassau County said it employs 16,784 full and part time and seasonal workers now, while Suffolk has 11,075. Both county figures include their respective community colleges but Nassau’s is swollen by 3,650 with the inclusion of the Nassau Unversity Medical Center, A. Holly Pattern Extended Care Facility and five federally qualified health care centers.

A decade ago Suffolk reported 11,612 full- and part-time workers but it’s unclear if the 2006 figure included seasonals, as does the new figure.

An aging population has created more demand for health care. Catholic Health Services has added 2,000 people since 2006, raising its total employment to 17,000; the group includes Good Samaritan Hospital Medical Center, St. Catherine of Siena Medical Center, St. Charles Hospital, St. Francis Hospital, and St. Joseph Hospital. Spokeswoman Elisa Gerber said the growth was due largely to the acquisitions of St. Joseph in Bethpage and physicians’ practices, along with organic growth.

Also growing is Winthrop University Hospital, whose 7,700 full- and part-timers represent a 19 percent increase from a decade ago. Spokesman J. Edmund Keating credited “continued organic growth of the Mineola hospital and its programs,” adding the emergency room was expanded about 10 years ago, a new trauma center is opening, and its ambulatory surgery center in Garden City is adding six operating rooms.

“Health-care employment in general has been growing super-fast,”said Shital Patel, the state labor department analyst for Long Island . “One reason is the aging population. Another is the Affordable Care Act; with more people insured, they’re seeking more health care.”

At Stony Brook University Hospital, included in the state government total of 20,304, employment now totals 5,814, representing a 22 percent increase from 2006.

Retailers also have grown. The Home Depot added more than 800 people in the last 10 years, a spokesman said, for a current total of 4,300. Walmart Stores Inc. employs more than 5,000 Long Islanders, almost 1,600 more than a decade ago.

“Retail has been a large job generator coming out of this recession,” Patel said.

Stop & Shop, another of the Island’s employment giants, now has 8,100 full- and part-timers, up from 7,000 a decade ago, with a contingent recently acquired from Waldbaum’s and Pathmark locations — all of which were sold or closed last year in the bankruptcy and liquidation of the Great Atlantic and Pacific Tea Co. (The figure for Stop & Shop was provided before the news this month that the chain would close its Freeport store in February. The company said it would reassign all 91 of those employees to other Stop & Shops.)

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Waldbaum’s employed 4,960 people on Long Island in 2006. Pathmark had 4,550 workers here that year.

The new list also reflects the shrinkage of some big banks. Citigroup, which had about 2,400 local workers in 2006, said it has 1,131 now. JPMorgan Chase dropped from 3,400 to about 2,500. The latter New York bank closed its Garden City offices last year, laying off 195, according to a state filing.

The names of some employers have disappeared, although many of their workers continue to labor at successor companies.

North Fork Bank, which employed 3,500 on Long Island in 2006, was taken over by Capital One in 2008, when it had more than 300 branches in the New York metropolitan area.

Eckerd, whose drugstores employed almost 4,000 Long Islanders in 2006, was taken over by CVS and Rite Aid during the last decade.

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Grumman is still here and is the second-biggest military contractor on the Island, but it has just 550 people in what’s left of its sprawling Bethpage complex, compared with about 20,000 at its height. Telephonics, a Farmingdale-based maker of radar and telecommunications systems, is the biggest local defense employer now, with about 1,100 employees.

One small but growing employment category often forecast to be important to the economic future of Long Island is pharmaceuticals.

“We don’t have the big presence that they do in New Jersey,” said chief economist John Rizzo of the Long Island Association, a business group. “I’d love to have Pfizer located here.”

Still, Contract Pharmacal and Amneal Pharmaceuticals, both in Hauppauge, each employ more than 900 people.

“It’s definitely an area that’s been growing,” Patel said.

Long Island’s employment changes also reflect the decline in its roster of locally based public companies, many of which moved out of the region or shrank when they were acquired.

In 2000, the Fortune 500 list of the largest publicly traded companies included former Long Island companies Arrow Electronics, Computer Associates, The Olsten Corp. and Avis Rent a Car.

Electronics distributor Arrow moved its headquarters to Colorado in 2011. Mainframe software maker CA Technologies, Computer Associates’ current name, moved its headquarters to Manhattan last year, leaving about 1,150 workers on Long Island, about half what it had a decade ago.

In 2000, Olsten, which provided temp workers to companies, was bought by Swiss rival Adecco. Adecco, which employed more than 4,600 people on Long Island in 2006, has moved most of its operations to Florida.

Avis was acquired by Cendant Corp., a provider of real estate and travel services. In 2006 Cendant changed its name to Avis Budget Group Inc., now based in Parsippany, New Jersey.

While the number of public corporations has dwindled, the number of company headquarters overall on Long Island has jumped in the 10 years ended in 2014 by more than 56 percent to 518, according to the latest data from the state Labor Department. These companies are overwhelmingly private, and tend to be smaller than the public companies. Their growth suggests that business employment has become more diffuse on Long Island.

Some Long Island employers declined to provide figures or didn’t return calls requesting information, such as Kohl’s, the Diocese of Rockville Centre, All Metro Health Care, Target, Macy’s and Estée Lauder.

Bethpage-based Cablevision Systems Corp., Newsday’s parent, declined to break out its Long Island employment. The company, which is being acquired by European cable and telecommunications and media company Altice NV, is listed by the states labor department as one of the Island’s top 10 private employers. (The department does not disclose the companies’ employment figures, deeming them proprietary.)

Retailer Target and All Metro Health Care, a Lynbrook provider of home health aides, are also on the state list of the largest private Long Island employers, but they declined to specify their Nassau and Suffolk workforces.

In one case, an employer was unable to provide figures comparable to those it released 10 years ago. Belmont Park, the horse-racing track in Elmont, said it has 1,241 full-time workers but was unable to provide a count of part-timers. In 2006 the track said it had more than 2,100 full- and part-timers.

Local economists say the changes in the last decade in the sizes and rankings of many major employers reflect trends in the local economy that already were underway a decade ago.

Said economist Irwin Kellner, a longtime student of Long Island’s economy who is now in independent practice, “The main groups like health care, education, finance and retailing — those are maybe not in exactly the same order, but they are still the prominent sectors that they were in 2006.”