The Department of Energy on Monday said that U.S. carbon dioxide emissions declined in 2012 to their lowest level in nearly two decades.

The departments’ Energy Information Administration (EIA) released a report on Monday citing a drop in energy consumption, which led to a 3.8 percent decline in emissions.

Residential consumers were responsible for half of the overall drop in energy-related emissions, while the transportation sector contributed to 22 percent of the decline.

The report also credited the natural gas surge for providing a substitute to coal-fired generation, which has a higher carbon output.