HOUSTON (AP) — Oilfield services company Baker Hughes Inc. says the number of rigs exploring for oil and natural gas in the U.S. rose by four this week to 1,858.

The Houston firm said in its weekly report Friday that 1,545 rigs were exploring for oil and 311 for gas. Two were listed as miscellaneous. A year ago there were 1,759 active rigs.

Of the major oil- and gas-producing states, Colorado gained three rigs, while Ohio and Louisiana gained two each. North Dakota and Texas gained one each.

Pennsylvania lost two, while Alaska, New Mexico and West Virginia lost one each.

Arkansas, California, Kansas, Oklahoma, Utah and Wyoming were unchanged.

The U.S. rig count peaked at 4,530 in 1981 and bottomed at 488 in 1999.

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