The number of rigs actively exploring for or producing oil in North Dakota is holding steady, though data show overall production is rebounding slightly.

State data show 74 rigs in active service as of Monday, relatively unchanged from one month ago. North Dakota is the second largest oil producer in the nation and, while diversified, its economy depends in part on the surge of oil taken from shale basins in the state.

The North Dakota Industrial Commission reported oil production in May, the last full month for which government data are published, at 1.2 million barrels per day, just shy of the all-time record posted in December 2014.

More than 90 percent of the oil produced in North Dakota comes from the Bakken shale formation. Bentek, a forecasting unit of energy reporting agency Platts, found Bakken production in June increased by about 100,000 bpd.

Energy analyst Sami Yahya said rig and production data show energy companies are learning to do more with less.

"Gains in efficiency have been swept every facet of the drilling and production operations," Yahya said. "Drill times have been reduced on averaged by three to five days in most of the major shale plays in the country."

The low-water mark for 2015 production was 1.16 million bpd in April, when the state rig count was 84. State-wide, the rig count is down 67 percent from its all-time high.

NDIC Director Lynn Helms said in July energy companies are working to improve their efficiency in the state. This, he said, has resulted in a rig count that is about five below what was expected if oil prices stayed below $65 per barrel.