The huge increases recorded by both Minnesota and Iowa indicate a higher demand for E85 from flex-fuel vehicle owners.

In Minnesota specifically, E85 sales in the first quarter followed the trend from end-2013 where monthly E85 usage average over a million gallons a month. The average price of E85 in the first quarter was $2.69 a gallon, which represented a 65 cent discount to regular unleaded E10.

The most current data available from the Minnesota Department of Commerce is up to April of this year with May's numbers expected to be released in the first week of July.

Including April's volume, total E85 sales for the first four months of 2014 totaled 5.04 million gallons, up 42 percent from the same period in 2013. The average price for E85 during this period was reported at $2.76 a gallon, which was 62 cents lower than regular unleaded E10. In recent weeks, E85 has been selling at a 90 cent discount to regular unleaded E10 as crude oil prices continue to rise.

As for E15, total volume reported for the first four months was 49,560 gallons. E15 was introduced in Minnesota in October 2013. Since then, the total volume of E15 sold, as of April 30, 2014, amounts to 78,807 gallons. There are currently seven stations offering E15 in Minnesota.