You put 20cc's of water in a 100cc graduated cylinder and fill the rest up with gas - that's 80cc more. Shake it up and when it settles the water/jokenol will now be 28cc if it is 10%. The reason they are going to 15% is because the Frikkin law says how much "renewable" fuel will be used annually and as gasoline consumption drops, which it has nationally, they have to blend in more. Oboma doesn't care about our stuff going bad cause we should all be driving chebby volts and besides like C4C, destroy a existing car and people will have to buy another, stimulating the economy.