Drilling for shale gas and light tight oil in the United States became much more efficient from 2007 to 2014. Bakken wells drilled in January 2014 produced 2.4 times as much oil as those drilled five years earlier. In the Marcellus Gas Trend, wells drilled in January 2014 produced more than nine times as much gas per day of drilling rig time as those drilled five years previously, in January 2009.[22][23]