Emissions awareness

So nearly three out of four motorists don't know how much Co2 their cars emit, according to this article in the Independent. I'm surprised one out of four do - it's a bit like being able to reel off the details of how much gas and electric your household consumes rather than how much the bill comes to. Fuel consumption - yes, engine size - yes.....but perhaps like most of the British public, I've never owned a new car, when specifications are very much on show so it's in second hand markets that these details need to be available?