There are now 12 different kinds of gasoline in the US, courtesy the Environazis. When you consider there are fewer oil refineries in North America today than 50 years ago, you start to scratch the surface of the problem.
Eric, m'friend, you're LOW.
As of 2002 (no information on 2003 changes, if any), there are now at minimum 43 required variational blends, which differ depending on jurisdiction and season of the year.