If you’re like most Americans, you haven’t been questioning the welcome drop in gasoline prices. You just fill ’er up and feel grateful that you’re spending less.But why has this remarkable drop come about? And what can we do to help keep prices lower?Some of it, unfortunately, is beyond our control. Worldwide demand for oil is down now. That always causes the cost of gasoline to drop.But the other side of the equation -- the part that is under our control -- has gone largely unheralded in many media accounts: the boom in U.S. energy production. Simply put, we’re producing...