I've not found more current data yet, but MN used 400,000,000 more gallons of gas in '97 than '87 (from 1,900,000,000 gallons to 2,300,000,000 gallons
)! P.S. 2,700,000,000 gallons in '04. Still looking.
"The gas guzzling reflects the fact that more people are driving, that nearly everyone is driving more miles and that motorists are buying bigger cars with lower gas mileage."
http://www.highbeam.com/doc/1G1-62578944.html
And MN was 18th in the U.S. in gas consumption. I have no reason to believe there's been a reversal in that trend, much less a slowdown.