The number of rigs actively exploring for oil and natural gas in the U.S. dropped this week by 11 to 1,848.

Texas-based oilfield services company Baker Hughes Inc. reported Friday that 1,410 rigs were exploring for oil and 435 were searching for gas. Three were listed as miscellaneous. A year ago, Baker Hughes listed 1,991 rigs.

Of the major oil- and gas-producing states, Oklahoma lost nine rigs, Louisiana and Pennsylvania dropped by two and California, New Mexico and West Virginia were each down by one.

Colorado added two rigs while Texas and Wyoming each gained two. Alaska, Arkansas and North Dakota were unchanged.

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