Business activity in the United States cooled more than forecast in May, a sign manufacturing may be leveling off after leading the economic recovery, Bloomberg reported.

The Institute for Supply Management-Chicago Inc. said its business barometer fell to 56.6 this month, the lowest since November 2009, from 67.6 in April.

Figures greater than 50 signal expansion. The group says its membership includes both manufacturers and service providers with operations in the United States and abroad, making the gauge a measure of overall growth.

The Institute for Supply Management’s monthly national factory index, due tomorrow, is projected to fall in May.