Five years after Congress rescued New York City from bankruptcy, midtown Manhattan is booming -- at least relatively -- so much so that it helped elevate the economic statistics released yesterday for New York State.

Since 1977, 160,000 new jobs have been created. More than 6,500 new hotel rooms have been built in the last three years, and commercial construction is feverish. Tourists crowd Fifth Avenue, buying the champagne truffles at Teuscher's chocolate store at $22 a pound, and buying out Saturday night seats for "Cats," the best-selling musical, months in advance.

Among the 10 largest states, New York had the lowest increase in unemployment during the first nine months of the year, according to new U.S. Department of Labor statistics. And the "strength of New York City" -- in contrast to its economic problems in the middle '70s -- is being viewed by department spokesmen as a "very significant" cause of the state's relative economic health.

Unemployment in New York State rose 9 percent in the first nine months of the year, with the number of people out of work averaging 668,000. Those figures were in sharp contrast to a 24 percent rise in New Jersey, the runner-up in this grim economic contest, and California where joblessness went up 41 percent.

This is not to say that the economic hard times affecting the rest of the country have completely bypassed the city. The overall unemployment rate for the city for September was 8.8 percent, compared with a national average of 10.1.

City spokesmen note, however, that the city's unemployment rate has been in the 9 percent range for the past five years, while the country's unemployment rate for the same time has increased sharply. New York City, with a shifting population, "held its own."

New York also has outpaced the nation in creating new jobs. The job market went up 1.6 percent in 1981, according to a recent Citibank report, as compared to a 0.6 percent increase nationwide.

The new jobs are not located in all parts of the city, however. They are concentrated in Manhattan, mostly in midtown. The hotels, the restaurants and theaters have been feeling a pinch, but compared to the rest of the country, the effect is slight.

"Customer counts here are off maybe 3 to 5 percent," said Charles Bernstein, editor of Nation's Restaurant News, an industry paper. "Compared to the rest of the country, where there's a real slump, that's minimal. Chicago is off about 25 percent, Detroit 30 percent. The Midwest has been very hard hit."

The same seems true of the theater. While Harvey Sabinson, executive director of the League of New York Theaters and Producers, said there is a 3 percent drop in ticket sales this September, compared to a year ago. He also notes that there are four fewer shows on Broadway (a drop of 14 percent.) And he said that this drop is minor compared to the touring shows. His group has 15 shows touring this year, as opposed to 22 last year, with a decline in receipts of 33 percent.

At home in the city, however, Sabinson can't complain.

"People still want to go to the theater and get out of the house," he said. "We've been affected less than most businesses."

This optimistic outlook is in contrast to the New York City of the 1970s. In the decade from 1967 to 1977, the city lost 400,000 jobs, most of them in manufacturing. In recent years, 160,000 jobs have been added in the "fire" section: finance, insurance, and real estate.

According to labor statistics regional director Samuel M. Ehrenhalt, the job situation in the city -- and the state -- has "gone flat. Jobs are hard to come by." Nonetheless, compared to national figures, New York City has done remarkably well in some areas.

"Commercial construction in New York City has been quite active," he said. "In the two-year period from '79 to '81, the number of construction jobs was up from 71,000 to 82,000, a l6 percent increase. Nationally, it was down by about 6 percent."

The cause of this financial good health varies, according to who is asked.

Spokesmen for Mayor Edward I. Koch are quick to credit the new jobs to Koch administration programs. Representatives of the tourist associations credit it to the economic importance of the city. The vice president of New York's Visitor and Convention Center, Jack MacBean, a big hometown booster, said New York City simply is "the top visitor and convention center in the world" with more hotels than London and Paris combined.

Jorgen H. Hansen, vice president and managing director of the luxurious Waldorf-Astoria, and past chairman of the New York State Hotel and Motel Association, takes a more global view.

Retrenchment is evident in the hotel business, Hansen said. The strengthening of the dollar in Europe has hurt the tourist boom of recent years. And yet the East Coast hotels -- and those of the West Coast -- have "suffered less than the midwestern sectors".

New York is "a gateway city from Europe and South America," he said. "It's got some of the largest financial institutions and it has the United Nations."