Check your car CO2 emission level

According to some recent publications, the level of CO2 emissions for the cars of a European country is not evolving since 2001, while there have been huge improvements with car engines. In fact, the problem is people just care about the diesel or gasoline consumption, since it is what directly impacts them.
But what about CO2 emissions? And how to check them?
This information is easily accessible for new models, since it is becoming a criterion for adding extra taxes, with the upcoming CO2 sticker in 2008 in France, or lower some in Belgium with lower taxes for cars under 120g/km.
But for older cars, how can you figure out if your car is somewhat green, or confront it with more recent models performances?
I have found a nice website: Ademe, a French site that allows you to get your car emissions level.
What I was able to seen there is, even if my car is a 8 years old Saxo VTS 1.4i, it is just as good as any similar new car with a similar engine: variation is only 1-2 g CO2/km and 0.1-0.2 l/100km.
Did really car running on unleaded gasoline evolved during the last 8 years? The only explanation I can find to this ridiculous difference is a change in electronic settings, running engines with poorer air/gasoline mix and so unsatisfying performances.
I think I will stick to my Saxo VTS for some more years...
Indeed some new technologies will soon become available, on the market, since gasoline hybrids are not very interesting, around 120 g/km, it is nice, but the overall consumption exceeds the one of diesel for the same car, and those are achieving far better performances!
Something interesting will come from hybrid diesel, that could reach 90g/km, but current hybrids are still missing some interesting improvements already used on electric public transportation systems, like super capacitors, that can absorb large amount of electric currents without the memory effects of the batteries.
Replacing part of the batteries with super capacitor, in sufficient capacity to store 70% of the car maximum cynetic energy (1/2*M*Vmax^2), would allow to store all the possible energy recovered when braking, and deliver it directly for the next acceleration phase, the rest would come from the batteries, that would only recharge when the car is cruising at a stable pace, avoiding too many charge/discharge cycles.
For the moment, I only see one usage for hybrids: gangstas, who want to cruise at low speed, without noise, running on electricity, to shoot other gangstas, and then accelerate on the electric+thermic engines to get a quick getaway...