Factory Usage Slips to 78.6%

WASHINGTON — The nation’s industries, responding to slack energy and auto markets and a cautious mood among consumers, used just 78.6% of their production strength in May, the Federal Reserve Board said today.

Capacity utilization in U.S. manufacturing, mining and utilities concerns slipped back 0.6% last month from a revised 79.2% in April, the Fed said. The index is weaker now than it has been since December, 1983, when factories operated at 78.3%.