Trinidad and Tobago has transitioned from an oil-based economy to a natural gas based economy. In 2017, natural gas production totalled 18.5 billion m3, a decrease of 0.4% from 2016 with 18.6 billion m3 of production. Oil production has decreased over the past decade from 7.1 million metric tonnes per year in 2007 to 4.4 million metric tonnes per year in 2017. In December 2005, the Atlantic LNG's fourth production module or "train" for liquefied natural gas (LNG) began production. Train four has increased Atlantic LNG's overall output capacity by almost 50% and is the largest LNG train in the world at 5.2 million tons/year of LNG.