HOUSTON, Oct. 6 (Xinhua) -- The number of active drilling rigs in the United States decreased to 619 this week, down by four from the previous week and by 143 from this time last year, according to the weekly data released by Houston-based oilfield services company Baker Hughes on Friday.
The active drilling rigs included 497 oil rigs operating in U.S. oil fields, down by five from the previous week; 118 gas rig
