WASHINGTON — The U.S. Postal Service said Thursday it lost $200 million during the year-end holiday season, despite a strong quarter of package shipping and expanded use of vote-by-mail in the November presidential election.

The results also reflect continued erosion in the delivery of first-class mail as well as expensive mandates for prefunding of its retiree health care obligations.

The post office’s report shows earnings of more than $1.4 billion between October and December 2016. But when effects of a $1.7 billion change in workers’ compensation liability due to fluctuating interest rates are excluded, the service says it lost money overall.

Operating income came to $522 million, down from $1.3 billion in the previous year.

The Postal Service has lost money for 10 consecutive years.