It does, but premium is only like ~$0.20/gal more expensive than regular here anyway. I don't remember the exact price, but it was probably like $4.18 or something.
Missouri octane gas prices are always linked. Regular is always cheapest, plus is always $0.15 more, and premium is always $0.15 on that. Gas got down to $2.79 for regular several months ago.
I remember around the time of the 2008 elections, gas was flowing freely at $1.39/gallon after being $3.99 a year or so before.