The North Dakota Department of Mineral Resources cites low crude oil prices but also windy weather throughout much of the month, which delays the fracking of wells, adding that it expects the slide to accelerate through May and into the summer.
There are 28 drilling rigs currently active in the state, up from 27 in May which was the fewest since July 2005; at its peak, North Dakota had 218 rigs drilling in May 2012.