WASHINGTON – The Postal Service has trimmed its losses to $740 million over the last three months by consolidating processing facilities, cutting hours for workers and post offices and reducing workers’ compensation costs, the agency said Friday.

Still, year-to-date, the Postal Service had losses totaling $3.9 billion, and the agency said that without help from Congress its financial woes will worsen.

The report for the financial quarter ending June 30 comes as Congress considers proposals to fix the agency’s finances. The agency lost $16 billion last year and is trying to restructure its retail, delivery and mail-processing operations.

Over the first nine months of its fiscal year, the Postal Service said 104 mail processing facilities were consolidated, career employee work hours were reduced by about 41 million and operating hours at 7,397 post offices were reduced.

The service wants to end most Saturday and door-to-door mail delivery. It also is seeking to reduce its congressionally mandated $5.6 billion annual payment for future retiree health benefits. The agency says ending Saturday mail delivery would save $2 billion each year.

Joe Corbett, the agency’s chief financial officer, said in a statement that “without comprehensive postal reform legislation signed into law, our hands are tied and we expect multibillion dollar annual losses to continue.”

The third-quarter loss was far less than its $5.2 billion loss for the same period last year. Postal officials said its cost-cutting and efficiency moves helped lower losses, along with a $918 million decrease to its workers’ compensation expenses due to interest rates.

Shipping and package revenue continued to be a bright spot for the agency, increasing 8.8 percent compared to the same period last year. That helped operating revenue rise 3.6 percent to $16.2 billion in the third quarter, compared to last year’s third quarter.

First-class mail revenue, the Postal Service’s most profitable category, declined by 0.9 percent compared to the same period last year. Total mail volume was 37.9 billion pieces, down from 38.3 billion pieces for the third quarter last year.

The Postal Service for years has been wrestling with declining mail volume and a 2006 congressional requirement that it make advance payments to cover expected health care costs for future retirees.

The Postal Service is an independent agency that receives no tax dollars for its day-to-day operations but is subject to congressional control.