The number of rigs actively exploring for oil and natural gas in the U.S. fell by 18 this week to 1,935 from the previous week.

Houston-based oilfield services company Baker Hughes Inc. reported Friday that 1,414 rigs were exploring for oil and 518 were searching for gas. Three were listed as miscellaneous. A year ago, Baker Hughes listed 1,916 rigs.

Of the major oil- and gas-producing states, Louisiana gained three rigs and Wyoming two. Texas dropped by 10, New Mexico lost five, West Virginia declined by three and Colorado and North Dakota each lost one rig. Alaska, Arkansas, California, Oklahoma and Pennsylvania remained unchanged.

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