ENERGY

Oil Rig Count Drops By 21: Baker Hughes Inc. reported that the number of working oil and gas rigs in the United States dropped by 21 last week to 668. The count lagged last year’s total of 799 rigs, the Houston tool maker said. Earlier this summer, the rig count dropped to a record low of 596. Last week, the tally climbed by 11 to 689. The count is a widely watched index of domestic drilling activity. It represents the number of rigs actively exploring for--not producing--oil and natural gas. The count peaked at 4,500 in the summer of 1986.