When the 2016 Toyota Prius was unveiled late last year, the fourth-generation model boasted a number of improvements over its predecessor. The driving dynamics were noticeably better, for one, and it featured new safety technologies like a pre-collision system, lane departure alert, and full speed dynamic radar cruise control. The styling was completely revamped as well, and while the interior looked a bit like a Stormtrooper’s skivvies to our eyes, we appreciated the new layout and upgraded materials.

Fuel economy is the name of the game in the Prius world, though, and in that sense, the new model knocks it completely out of the park. According to a new batch of tests by Consumer Reports, the 2016 Prius is the most fuel efficient vehicle the group has ever tested.

The hybrid hatchback averaged 52 mpg combined (43 mpg city, 59 mpg highway) in Consumer Reports’ trials, besting the previous Prius’ figure of 44 mpg and topping the original gas-sipping king by 1 mpg. Can you guess what the old record holder was? Turns out it was the original Honda Insight, which set a lofty benchmark of 51 mpg way back in 2000.

There isn’t one overarching reason for the 2016 Prius’ staggering mileage, rather, there are many. The new body’s drag coefficient of 0.24 is one of the lowest of any mass-production vehicle on the market, and the gasoline engine is physically smaller, lighter, and overall much better at managing thermal energy than its precursor. Not only that, the CVT gearbox has been streamlined, and the battery pack — now made with a lithium polymer instead of a nickel-metal hydrid in most versions — is far superior at storing and delivering power to the wheels.

Read more: Toyota quietly zips even further ahead of the competition with the 2016 Prius

Obviously, 52 mpg combined is impressive, but if you’re looking to save even more at the pump, you’re in luck. A new plug-in version called the Prius Prime is headed for showrooms in late fall, and is expected to return an MPGe rating of 120 or above. Read more about the Prius Prime right here.