Nice data. It shows how technology has come a long way. Even though weight has gone up, due to safety and more equipment, fuel consumption has maintained and even decreased.
Yes a car would have even better gas mileage if it is made lighter, but in reality, no one is going to buy a 2010 Civic that has the features and safety of a 93 Civic. If you want a lighter civic, strip it out, or buy a old car, simple as that