I filled up at Meijer this morning. Here are the stats:
Price E85: $3.30 a gallon
Price 87 Octane gas: $3.80 a gallon
Gallons E85: 5.000
Gallons 87 Octane: 9.004
Gallons left from tank 6 (@~31.343% ethanol): 2.396
I'm assuming that the E85 is 75% ethanol, 100 octane.
Ethanol content of tank #7: 32.939%
Octane of tank #7: 91.629
Tank 6 finished with a mileage of 23.5. Average speed was 28mph.
After I filled up, on the way to work, I was briefly at 29 mpg at 45 mph average speed. I don't think highway mileage is any worse on E85.