The University of Michigan’s Transportation Research Institute (UMTRI) tracks the average fuel economy of vehicles sold each month and for January found that this number hit a record high of 24.5 mpg. This number is up from the revised value from December, and up 4.4 mpg from the index’s original value in Oct. 2007, the first month of monitoring.

According to UMTRI, these recent improvements reflect the improved fuel economy of 2013-MY vehicles rather than other factors. UMTRI also tracks average monthly greenhouse gas emissions. UMTRI found that the average stood at 0.82. This value takes into account the amount of fuel used per distance driven and the overall amount of driving. This value is an 18% improvement since Oct. 2007.