Despite steadying mail volume and revenue, the U.S. Postal Service reported a net loss of $2.1 million for the month of May, the eighth month of its fiscal year. The Postal Service has lost $10.1 billion year-to-date.

Total mail volume increased in May by 1.1% over the year-earlier period, to 13.1 billion pieces, with monthly revenue up 3.1%, to $5.3 billion. One other bright spot was shipping services, which saw volume double, to 274.8 million pieces, and a 40% boost in revenue, to $1.1 billion for the month.

Standard mail, used most often for commercial mailings, experienced a slight increase in volume. However, first-class mail continued to fall both in volume and revenue. Also, the Postal Service was obliged to pay $1.7 billion to prefund retiree health benefits and workers compensation for the month. Operating expenses rose 13.4%, driven by higher worker compensation costs and benefits.