Did you have a computer in 1987? Even if you didn’t, you know how much computers have improved in 20 years. With that in mind, doesn’t it seem odd that car makers haven’t been able to improve fuel efficiency during the same timeframe?

The EPA has announced that the average fuel economy of passenger vehicles in the U.S. is 21 mpg. That number has actually gotten worse since 1987, when the average was 22.1 mpg. It is a slight improvement over 1997, though, when mileage hit 20.9 mpg.

What’s to blame for this lack of development despite improving technology? Simply put, it’s weight. The average vehicle now tips the scales at 4142 pounds, the highest in history. The average had previously peaked at 4060 pounds in 1975, then dropped all the way to 3220 pounds in 1987 before climbing steadily to the heights of today.

We might have lighter body materials, but we negate those with more safety features, luxury items, and more performance. 0-60 times have decreased from 13.1 seconds on average in 1987 to 9.7 seconds now, while horsepower jumped from 188 to 219. That performance doesn’t come from smaller, lighter engines.