Why can't you just calculate the premium based on 201 data points instead of 200, the 201-point being whether it's an electric car, hybrid, or regular car?
I think the "200 data point" line means "200 cars that crashed" and that there are too few electric cars around to do analysis on "electric cars with 30k miles driven, and owned by people without college degrees" or whatever- so they just look at "all electric cars" in one bucket.