HOUSTON (AP) — The number of rigs exploring for oil and natural gas in the U.S. declined by four this week to 909.

That's up from the 557 rigs that were active a year ago.

Houston oilfield services company Baker Hughes said Friday that 737 rigs sought oil and 172 explored for natural gas this week.

Among major oil- and gas-producing states, Texas gained five rigs and Oklahoma and Wyoming each increased by one.

Louisiana lost three rigs, North Dakota and West Virginia each declined by two and Alaska, Colorado, Kansas, New Mexico and Pennsylvania each lost one.

Arkansas, California, Ohio and Utah were unchanged.

The U.S. rig count peaked at 4,530 in 1981. It bottomed out in May of 2016 at 404.