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Members of Boeing’s largest union approved a new contract on Monday, ending a weekslong strike that was one of the country’s most financially damaging work stoppages in decades.

The contract was endorsed by 59 percent of those voting, according to the union, the International Association of Machinists and Aerospace Workers. The union represents about 33,000 workers, most of whom make commercial airplanes in the Seattle area. More than three-quarters of the members voted on the contract.

The union said its members, who had resoundingly voted down two previous contract offers from Boeing, could return to work as soon as Wednesday but must be back by next Tuesday. The strike began on Sept. 13, after the union rejected the company’s first proposal.

“You stood strong, you stood tall and you won. This is a victory,” said Jon Holden, the president of District 751 of the machinists union, which represents the vast majority of the workers covered by the contract.

The new contract will raise wages more than 43 percent cumulatively over the next four years, an improvement over the two previous offers. The first proposal would have raised wages just over 27 percent.

Union leaders and Boeing had urged the workers to approve the deal. The union’s leadership had warned that future offers from the company could have worse terms than this proposal.