Michigan ranked near the bottom of all the states in terms of the average increase in mpg gained from swapping older cars for newer ones during the cash for clunkers program earlier this year. The Detroit News reports that disappointing news:

According to a Detroit News analysis, Michiganians who swapped old vehicles for vouchers worth up to $4,500 toward the purchase of a more fuel-sipping model, averaged a gain of 8.27 mpg, compared with 9.2 mpg nationally.

Michigan ranked 50th in fuel-efficiency improvement among all states and the District of Columbia — in part because Michiganians were less likely than other Americans to swap a pickup or SUV for a passenger car. Only Louisiana, where the average improvement was 7.9 mpg, ranked lower…

Nationally, buyers swapped vehicles averaging 15.8 mpg for new vehicles averaging 25 mpg. In Michigan, however, the clunkers averaged 15.7 mpg and the new vehicles 23.9 mpg.

That’s still a pretty significant increase in fuel efficiency for 700,000 cars on the road, however. The final version of the program only required that the new car have a fuel efficiency of four miles per gallon above that of the old car being turned in, but even in the worst of the states doubled that number. And the study noted that Michigan’s low ranking was due to brand loyalty to American-made cars:

Domestic brand loyalty was among the factors contributing to Michigan’s low ranking in fuel-efficiency gains. Michiganians buy domestic vehicles in higher numbers than consumers in other states, and cars and trucks built by Detroit’s Big Three are heavier and less efficient, in total, than their foreign rivals.

For example: 81.1 percent of Michiganians who turned in a domestic vehicle replaced it with another model from a Detroit automaker, compared to 42.8 percent in the rest of the nation, according to an analysis of data from the National Highway Traffic Safety Administration.

More than 57 percent of Americans who traded in a domestic vehicle through the program — which supporters also hoped would boost sales of domestic brands — bought a foreign make. In Michigan, however, less than 19 percent fell into this category.

Of course, being a foreign brand does not necessarily mean the car wasn’t made in the United States by American workers.