Patterson-UTI Energy Inc. reported June 5 that its average drilling rigs operating totaled 158 in May, down by eight from April and down by 13 from March.

For April and May, the driller had an average of 162 drilling rigs operating.

Average drilling rigs represent the number of the company's drilling rigs under contract. Patterson cautioned that numerous factors could affect its operating results, and a trend in the number of drilling rigs operating may or may not be indicative of its financial performance.