The average gasoline consumption by Americans is at its lowest level in at least 30 years, according to a report from the University of Michigan’s Transportation Research Institute.

The report found that gallons of gasoline consumed per person, driver, vehicle and household have fallen a combined 14 percent to a level not seen since 1984.

"Despite population growth of 8 percent, the absolute amount of fuel consumed by light-duty vehicles decreased by 11 percent during the period 2004 — the year of maximum consumption — through 2013," said Michael Sivak, a research professor at UMTRI and director of the Sustainable Worldwide Transportation research consortium.

Sivak says the amount of fuel consumed per driver has dropped 16 percent since 2004 and the amount of fuel consumed per vehicle has dropped 14 percent since 2003.

The report also analyzed changes in the number of vehicles and distance driven per driver and vehicle and found both measures are at their lowest since the 1990s. Some contributing factors for the decline are increased use of public transportation, increased telecommuting, and urbanization of the population, according to Sivak.

"The reductions in the fuel-consumption rates reflect, in part, the added contribution of the improvements in vehicle fuel economy," Sivak said. "Overall, the combined evidence from this and the previous studies indicates that—per person, per driver and per household—we now have fewer light-duty vehicles, we drive each of them less and we consume less fuel than in the past. There is no evidence in the 2013 data that the peaks in the rates that we experienced about 10 years ago were temporary."