The current average state excise and tax per gallon of gasoline is 30.4 cents, according to the American Petroleum Institute, here.
The federal excise is 18.4 cents.
Today's national average price per gallon is $3.464, as shown here.
This means that today's national average base price per gallon is $2.976 per gallon.
That yields an average state excise of 10.2 percent at today's base price, and an average federal excise of 6.2 percent.
