Economic activity in the U.S. manufacturing sector expanded in April but at the slowest rate since December, according to the purchasing managers index for manufacturing released today by the Institute for Supply Management. The index fell to a reading of 50.7 in April, down from March’s reading of 51.3. Readings above 50 indicate growth.

The employment portion of the index fell to a reading of 50.2 in April, down from 54.2 in March.