HOUSTON (AP) — The number of rigs exploring for oil and natural gas in the U.S. rose by 13 this week to 870.

A year ago, 420 rigs were active.

Houston oilfield services company Baker Hughes Inc. said Friday that 697 rigs sought oil and 171 explored for natural gas this week. Two were listed as miscellaneous.

Texas added 11 rigs, Oklahoma gained three and Wyoming gained one.

New Mexico lost three rigs.

Alaska, Arkansas, California, Colorado, Kansas, Louisiana, North Dakota, Ohio, Pennsylvania, Utah and West Virginia were unchanged.

The U.S. rig count peaked at 4,530 in 1981. It bottomed out las...