Brazil has had an aggressive ethanol policy since the 70s Oil crisis. I dont have more time to find the numbers - but this suggests that all gasoline already has high proportions of ethanol...
"The percentage of ethanol blended in gasoline can vary from 18 to 25 percent according to the Provisional Measure #532 of April 2011. In 2011, the ethanol blend rate was dropped from E25 to E20 due to low availability."