The USA produces around 13.6 billion gallons of ethanol out of the corn that is produced per year as there are a lot of bushels of corn grown in the USA each year and about 40 percent of corn grown in the USA is used for ethanol production.
One bushel of corn produces around 2.8 gallons of ethanol and there are a lot of ethanol production facilities that produce a lot of ethanol.
The type of corn that is used for ethanol is Dent Corn which is the most common type of corn for use in the production of ethanol that we use in our vehicles.
The corn used in ethanol production is yellow dent corn and he endosperm in the dent corn is mostly composed of starch which is the energy storage, and protein for germination of the corn.
Around 40 percent of the corn grown in the USA is used for production of ethanol which is then added to gasoline to make the gasoline cheaper as well as make the gasoline go further and last longer.
If we didn't use ethanol in the gasoline then the gasoline we have without the ethanol will not last as long and we would run out of regular gasoline much sooner.