Oilfield services company Baker Hughes Inc. says the number of rigs exploring for oil and natural gas in the U.S. this week declined by six to 842.

Houston-based Baker Hughes said Friday that 644 rigs were seeking oil and 198 explored for natural gas. A year ago, with oil prices about double the prices now, 1,931 rigs were active.

Among major oil- and gas-producing states, Colorado, New Mexico, Ohio and Utah each gained one rig.

Louisiana and North Dakota lost three rigs apiece, Pennsylvania declined by two and Kansas and Texas were down one each.

Alaska, Arkansas, California, Oklahoma, West Virginia and Wyoming all were unchanged.