The U.S. Postal Service’s financial struggles continued into 2012, as the agency reported a $5.2 billion loss for the three months ended June 30 despite improved revenue from shipping and packaging.

The service said declining volume in the type of mail that most Americans use and a congressional mandate to prefund retirement health care benefits continued to cause deep losses.

But the Postal Service also reported 9% growth in revenue from shipping and packaging, which brought in an extra $3.3 billion — although that was not enough to offset other losses. The $5.2 billion net loss was worse than $3.1 billion loss posted during the same period in 2011.

First-class mail — the kind most Americans use to mail letters and pay bills — took another hit in the latest quarter, with volume falling 4.4% from the previous quarter.

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