There's a few places that keep track of this data, http://carsalesbase.com/european-car-sales-data/bmw/bmw-i8/ http://carsalesbase.com/european-car-sales-data/b

There's a few places that keep track of this data, http://carsalesbase.com/european-car-sales-data/bmw/bmw-i8/ http://carsalesbase.com/european-car-sales-data/bmw/bmw-i8/ for one. I have seen sales figures for most brands shown publicly, so I don't think it's something they keep to themselves.