Right, but be careful with that line of thinking. In terms of cents of economic damage per km driven, yes, gas cars are better driven in the boonies; but watch out! That isn't where most people are driving. Most people are driving around cities. So this map makes it look like electric cars and gas cars are more toe-to-toe than they are.
And really, most of the dirtiest coal power plants are nearing end of life, so if you look at the trending, even in the USA, which has a very dirty energy grid, electric cars are going to be much less pollutant than gas cars everywhere and very soon.
Also note that the car in question, the Ford Focus, is one of the least pollutant gasoline cars out there. Electric cars scale up better than gasoline ones.