U.S. employers added 148,000 jobs in September, a discouraging report that might still be too optimistic about the job market.

The Labor Department report is based on data collected before the recent government shutdown even started, so it doesn’t factor in the resulting furloughs. Adding to the uncertainty, the coming data releases will be delayed and distorted by the partial shutdown, making it difficult to assess the underlying health of the economy.

Weakness in the hiring figures is expected to further delay the Federal Reserve’s decision to start tapering its stimulus programs.

“The labor market lost, rather than gained, momentum over the summer, leaving us with less than a desirable cushion just as the government was shuttered in response to political shenanigans,” said Diane Swonk, chief economist at Mesirow Financial.

The pace of employment growth in September was slower than the average rate over the previous year, which was about 185,000 jobs per month. The unemployment rate settled at 7.2, down from 7.3 percent, an insignificant statistical change.

The biggest net hiring gains in September were in construction, wholesale trade, and transportation and warehousing.