Over the previous decade, the identical international locations — Saudi Arabia, Russia and the U.S. — have remained Nos. 1-Three in oil manufacturing. However the U.S. has elevated its manufacturing by 36% in that point. The acquire is generally as a result of so-called “shale revolution.” U.S. know-how to get oil from deep underneath rock — in addition to falling demand in China and different once-red-hot economies — has created an oversupply. The per-barrel value has fallen beneath $70, its lowest level in about four-and-a-half years.