This is interesting as I watched a programme about it in the UK tonight.
Over here the ethanol content is 5% max.
As far as I understood it the only reason that increasing it is good for the environment is that it requires the growth of corn (ethanol in gasoline comes from corn oil).
However, CO2 emissions are somewhat related to ethanol content, so while it might be good for the environment at ground level, it destroys the ozone layer and speeds up climate change if you increase it.

Something else really interesting that came out.
I recall your 'regular' gas is 89 RON. We have nothing that low here - choices are 95 or 98.
The same (German) vehicle in the US that got 22 miles to the gallon with 89, got 34mpg over here using 98, and also needed twice as much maintenance. I guess our gas isnt really two and a half times as expensive as yours after all