Most states don't have a single charging station...not surprised. It looks like Cali has more than the rest of the country combined but I guess there's a few in the northeast too.
They seem to group them only in the most densely populated areas which kind of makes sense but then try going from Portland to San Francisco in an electric car and you'd get stranded near Eugene, or going the other way you'd get stuck around Redding. If they were smart there'd be a charging station every 100-ish miles on the major routes like i5.